Why waste your breath ranting about influxes of (insert major fandom here) cosplay at a convention or some other cosplay event? It’s not like those people are actually hurting you. Just ignore it, find some friends to spend time with (especially those that you don’t get to see outside of the event), and have fun. Hell, if you poke around hard enough you’ll find at least one or two cosplays you know and like. People are going to cosplay what they wish, so long as their choice of cosplay isn’t grossly offensive or a safety hazard to others. To quote an old meme: "Deal with it", or just leave.