I would argue that being polite and inoffensive isn't even necessarily 'kindness'. There's nothing 'kind' about enabling someone hooked on drugs or any other destructive habit until their addiction finally destroys them & sends them into an early grave, after all. I would categorize the coddling & enabling of people's worst impulses demanded under the name of 'tolerance', 'kindness', 'empathy', etc. by the left as more just 'being nice', in the same sense that white Minnesotan liberals are putting their 'Minnesota nice' on display for all those Somalis screwing their state up.

There's a pretty good collection of 4chan posts that nails the difference from many years ago, and which I think still absolutely applies to this 'Nice Doctrine'.