While Machismo answers the question asked, the reason why there is that reaction is mainly a lack of understanding about how and why compact cranks exist.
Obviously, you can look at it and say to give us better climbing (easy) gears.
But what many people miss is the rear ratio changes.
The race standard for many years was 53/12.
That is, the hardest gear, made up of the largest tooth count in the front, and the smallest in the back, was a 53 tooth front chain ring paired with a 12 tooth rear cog.
A few years back, Shimano started making an 11 tooth rear cog.
It was originally intended for pro racers and time trialists.
Somebody got out the calculator, and realized that with that 11 tooth rear cog now available, you could decrease the size of the front rings, and get the same gear ratio, or slightly faster .
That decreased front ring size allowed better climbing ratios when paired with the large cogs on the cassette, but also maintained the high gear speed racers are used to.
Someone riding a properly setup compact crank, actually is pushing a harder, faster gear than the 53/12 "standard".
That said, if you pair a 53 with the 11 tooth, it will be faster yet, but not often do you find the legs to push that combo.
I've included gear inch charts for both, so that you can see for yourself how it works out.
If you are not aware, gear inches are a comparison to the effective diameter of a direct drive wheel, when gear advantage is accounted for.
bicycles.stackexchange.com/users/1259/zenbike
Pedalling with compact cranks is supposed to be easier.
So people who take great pride in how strong they are and how fast they can go
don't like when you're able to do the same with (apparently) less effort.
You can compare to being passed by electric bike while climbing, some people just feel the person on the e-bike doesn't "deserve" to be that fast and it hurts their ego.
It's pretty much
a "I'm manlier than you" thing, like "I use brute force to be fast, while you needed to have a mechanical advantage".
Add to that the fact humans don't like change and it's in our nature to frown upon new things trying to go against old "standards".
The blog
Why not tri? has a nice little article about Compact vs Standard.
bicycles.stackexchange.com/users/417/dee-see
Machismo.
Compacts came about to alleviate the high gearing of a standard crankset's gearing without inheriting the troubles that come with a triple.
Compacts are naturally geared lower than standards.
Some people (incorrectly) see lower gearing as a sign of weakness.
Some of those same people will serpentine their way up high grade mountain roads because they thought they could push standard gearing but can't.
Which gearing you go with is purely a matter of overall strength and riding style.
Neither one is the wrong decision in the right situation.
I've done races before where in the description it has read "compact gearing highly recommended.
" That's a fair warning to heed.
bicycles.stackexchange.com/users/2598/joelmdev
I think that compact (lower gears) supposedly would imply the person isn't strong enough to spin higher gears, or actually needs that low gears to be able to climb properly.
In any case, I think most people doesn't even know there is a difference on crank chainring sizes, not to mention they could very well prefer one over another.
I for one ride internal gear hub,
and I have one 46t and one 39t chainring.
When I feel fit and wanting to speed up, I install the 46t.
When I am more lazy, or more feel more tired for a longer period, I install back the 39t.
This scorn stuff, or "weakness" stuff, is all inside people's head, I would say.
bicycles.stackexchange.com/users/2355/heltonbiker
I have no experience with the egos of aspiring cyclists, but I can note a (small) technical difference
A sprocket with a lower tooth count will require the chain to bend more sharply as it engages with the teeth.
The effect is complicated to describe, but it may be thought of qualitatively as the end of each successive link meshing onto the sprocket whipping around and causing an oscillation in the slack side of the chain.
This effect dissipates the majority of drivetrain energy lost through the chain.
The magnitude of the effect is nonlinear (roughly proportional to the square of angle of articulation)
so the difference is negligible at the chainring, but there is a non-negligible difference between 11T and 12T on the rear.
It's something like 0.4% higher theoretical drivetrain efficiency for the 12T.
bicycles.stackexchange.com/users/26330/Bill
Yep, a combination of maschisimo and most importantly a sad case of "It's not what the pros do".
Yes, you'll never see a pro racer on a compact, and rarely one on aluminum wheels at that, but somehow a lot of guys love to hate it.
Despite the fact that as the gearing post about mentions, you're rarely even in gears that make a difference in all but an out and out sprint.
Funny thing though, show up to a group ride and someone may laugh at a compact, yet show up with cyclocross gearing (like a 46/38) and suddenly you're he-man?
bicycles.stackexchange.com/users/2760/conipto
Insecurity and attitude.
As witnessed in answers to this question, the very presence of a compact crank leads to lectures about how pro racers can ever use regular crank and ranting about how regular crank users "serpentine their way up high grade mountain roads because they thought they could push standard gearing but can't.
" This gets old pretty fast.
bicycles.stackexchange.com/users/10595/ojs
At the cafe stop on my local Saturday ride a few of the guys we chatting and one guy asked an other if he was riding a compact drivetrain. The other guy objected loudly and they then joked with other members of the group suggesting they were riding compacts.  Why would the notion of riding a compact drivetrain attract such a response?
Why might a compact drivetrain be frowned upon?
bicycles.stackexchange.com
<bike-culture><compact-crankset>
bicycles.stackexchange.com/questions/6727
bicycles.stackexchange.com/users/129/Greg B
The general consensus is that frowning on a compact drivetrain is due to machismo and, more generally, to people's dislike of change. Another reason to disapprove of it is that it is not used by professional cyclists. The idea of the compact drivetrain is to make pedalling easier. Both standard and compact drivetrains are fine and the choice depends on the individual cyclist. There are some technical differences between the two types and compact gears tend to be geared lower than standard ones. They are not normally used by professionals, and can have a reputation as an easy option for weaker riders. This can generally be dismissed as machismo and misunderstanding of the compact gear's role.
This is mostly due to pride and misunderstanding of the role of compact gears, especially as they are not used by professionals. Compact gears alleviate the high gearing of a standard crankset without the need for a triple. There are small technical differences and the right choice depends on the use and personal preference.