"That particular (algorithm|technology decision|doohickey) is bad for the following three reasons, this alternative is better because it's !(those three reasons), is less work, easier to maintain and also offers us the following three affordances. I've used this in a number of other installations and can vouch for its reliability and ease-of-use.

This categorically does not work"

meh, if that gets the job done faster then say it. The chance of a 20 minute argument vs a weeks long delay? I'll take the 20 minute argument.

But then again, leading questions get my back up. I'm a "say what you mean, don't hint at it" type.

If I get offended because someone else knows better and tells me so without being rude, then it's my problem (and my insecurity), not theirs.