system
A chat on subreddit /r/wallstreetbets
human
it means they are fucking you over. Say you want to sell your put at $34, then they put up a artificial buy order at $32 ( although $34 bid may still be available). Then the HFT guys use that $32 option and sell it into market for $34. So you lose $2 and this happens when both buying and selling.

gpt
I'm gonna need this dumbed down a bit more.