You can disagree without being angry or cynical. That you think you need to be cynical, pissed, or "pissing on the happy-go-lucky-parade" to disagree and engage with real problems is the notion I hold issue with.

>So, they wouldn't be doing it unless they really had to.

I can think of a handful of reasons why they may do so.

Being a contrarian is not hard. It certainly does not mean that the person being a contrarian is right (or right to do so, especially if the methods is being an insufferable colleague).