I agree completely, and I think too many online spaces make room for cynicism not realizing that it contributes nothing, and ruins the experience/eventually pushes out of anyone who isn't cynical.
When I was a mod on /r/StarTrek we had a rule (it's also thankfully a rule here) "be constructive" which was basically "Criticism is OK but cynicism is not. If you want to present 'criticism' you need to behave like a real critic and cite examples, not just rant". And let me tell you that rule really upset a lot of folks who felt that had a right to pee in the communal pool.