From what I have learned, a “fake ask” is meant to scare people into buying into it and thus keep the price down. The person doing it doesn’t really want to sell all of his/her shares, and if momentum starts building and the ask starts getting slapped hard, the “ fake asker” takes the order down to avoid selling shares too low.
A fake ASK is usually a MM not showing how many shares they actually have and keep the same block on the ASK even after throwing slaps at it without reducing its number.