i'm a startup co-founder, i hire all the time.
if i asked someone what their salary requirements are and they said 200k or 300k i'd immediately interview them to see if they're worth that much. i would take it as a personal challenge to see if i could stump them, and if i couldn't, i'd start negotiating their salary on the spot.
some people get paid MILLIONS OF DOLLARS! how the hell d'ya you think they got that much? they asked for it!
people who don't want to "reveal" their salary requirements like it's some big huge secret have probably never hired anyone in their life.