I think we need to clear up one thing first: It does not break your browser. Fullstop.
Now as far as it comes to being slow and/or unresponsive and/or crashing, yes, that can happen...but that can also happen on every other page on the internet. All modern browsers can recover from such a disaster in one way or the other, and I haven't heard of a data loss or even an OS crash, caused by a browser, in a long time. So a crashing browser is not a problem, it's an inconvenience, annoying, yet not problematic in 99% of cases.
So, should we stick a warning sign on that question? No, I don't think so, visiting random pages when flicking through your Google results is more dangerous then visiting this question.
Should we do something about this question slowing down or even crashing browsers? Absolutely! We have the opportunity to report it as a bug to the developers with a reproducible and secure site. Remember, most sites which slow down your browser or make it crash are not exactly of the trustworthy kind, but with this question we can give developers a safe site which they can use to reproduce and track problems in.
Should we allow "actively malicious" stuff in that question? No, never, flag and remove on sight!