Mounting evidence, such as? Personally, given the standard of debate on a lot of forums these days, I could frankly support a lot more stifling.
Whilst I'm not going to argue your point on debating standards (because I agree it's woefully low) but I believe that is partly due to people not being able to say what they think and have to caveat everything they say.
I happened across a live studio debate a few months ago and it seemed that the whole audience were of the 'SJW' type - i.e. getting offended on others' behalf, not their own. It was amusing to watch them tie themselves in verbal knots over what they felt they could, or more to the point what they could not, say whilst discussing whatever the issue at hand was.
There was so much caveating going on it was hard to actually discern what the subject being discussed actually was.
The problem is the wording of law invites intolerance of someone else's point of view, it encourages people to 'be insulted' so that they can claim the other party is 'x-ist' or whatever so they can shut them down and not have to address the (often) valid points that are being raised.
I could write 500 words on a worthy subject, and even if I managed to convey constructive ideas and practical means of employing those ideas it would only require one badly worded sentence for the whole thing to be shot down in self-righteous flames and all the valid points would be ignored, even if those very same points could do a lot to help the very people who are flaming.
It is insane.
As for examples, there are too many to list. The first hit I got when I looked was an article from several years ago that mentions a few abuses of this power and why it needs an overhaul. If you want more have a look for yourself.