Gerrymandering is both over-sold and under-sold as an electoral evil or barrier.

It's under-sold in that it really can devolve to the level of politicians selecting their constituents rather than the other way around. But generally as often as not this benefits a political party in one district it benefits the other party in another district. 

But it is also over-sold. The biggest barrier to equal representation is voter self-segregation by geography. Denver is a Democratic city. But it would be just as Democratic if Democratic voters comprised 55% of ballots cast instead of the 85% of ballots cast that is the typical result. Running up the vote in Denver must mathematically mean "running down" the vote outside of Denver. 

The core problem is that the political parties both want to avoid the most extreme measure - drawing lines to maximize competitiveness. That would would require "anti-gerrymandering" by overcoming geographical segregation and lumping together the dislike.