Sometimes it is easier to remember what to do by also giving examples of what not to do. So let's try to describe some ways how to ruin a community.

Tentatively agree. Just so long as the intended mnemonic isn't "Let's take these examples of stupidity and do the opposite". Some of these are even worse if taken to the other extreme than to the one you warn about. Reputational pressures are perhaps the most desirable but with moral and institutional pressures it can be a good idea to oppose inappropriate applications forcefully but encourage desirable applications. In fact, one of the best uses of both moral and institutional pressures is to apply them to pre-empt future misapplication of the same. (Both tools are necessary but dangerous.)