that sort of faux-diplomacy annoys me more personally because it always is blatantly obvious what the person is trying to communicate, and it sounds like it comes out of some kind of corporate PR training session. Like, if someone thinks what I does suck I always invite people to tell me so. If you're trying to sugarcoat it not only is it obvious that you think the idea sucks, you also think I can't accept your opinion, that's worse lol.
I think in general, not just in the workplace, people are very fine-tuned to noticing false compliments or underhanded criticism, and it's always worse than just playing it straight.