>>34849811A lot of people whining about Misty were people who barely watched anything after Johto, same reason you saw them barely talk about Dawn or anyone after. Pokeshippers also went to war with Pearlshippers when DP was airing, I remember Misty fans would call Dawn "too girly" or "wearing a short skirt/princess and is too bland" etc on forums all the time. So it's not like these Misty fans only signaled out May, etc.
By the time BW started most of them finally left the fandom because it became obvious once and for all Misty would never return to the main cast, as Brock finally left after DP too, and now most of them are on places like tumblr or deviantart. Amourshipping also made them crazy for a while but for the most part they don't care.
Oddly enough most Misty fans I've seen online now say May is their second favorite female companion. Some like Dawn too, so I guess these Misty fans changed their minds as they got older.