Which in practice just means that everyone labels anything they don't like "intolerance", bans it and toddles off congratulating themselves on how tolerant they are.

I have no idea what the solution is. I suspect anyone coming up with one would win all the Nobel Peace Prizes from now until the end of time. I do think it's a useful rule of thumb that if you're not finding tolerance excruciating and infuriating at times, you're not really doing it.