I have unfortunately seen all the things you describe, for example see any thread about PHP, or the thread about perl and random syntax, or about using an ORM for SQL.
I've seen it in threads about social issues as well, although none come to mind right now.
I've seen it too, and while disturbing, I don't think it's representative of the HN population as a whole, and I certainly don't think it's representative of the types of people who would initially be picked. The goal of my proposal is to counteract the people who do engage in those unwanted behaviours by giving proportionally more voting power to those who demonstrate that they don't.
I've seen it in threads about social issues as well, although none come to mind right now.