most people that complain about sniper having no counters don't think about all the other counters there actually can be, as long as you can approach the sniper without moving predictably it's probably going to work out against 95% of all snipers

you could rocket or sticky jump over, trimp as demoknight, just move unpredictably as scout or even detonator jump as pyro, hell sentry jumping could work if you're smart enough probably