Here is a new post at EconLog in which Bryan Caplan discusses how signalling contributes to the status quo bias.
The lesson: In the real world, signaling naturally tends to ossify behavior - to lock in whatever the status quo happens to be. If you're an optimist, you can protest, "It's only a tendency." But even an optimist should admit that this tendency leads to atypically slow and unreliable progress.
I think it would be interesting to analyze in more detail what you mean by "intolerance". We might distinguish the sort of "intolerance" that is expressed by mass violence against its target, and the sort that is expressed by simply not taking the target's claims very seriously.