I was going to write at length about my concerns on this topic, and then I decided not to. Because it's entirely possible that one day many years from now, a prospective employer/insurer/whatever finds such a comment and flags me for it.
That's the cooling effect in a nutshell.
This is why you should use pseudonyms and strive for anonymity. It's trivial to signup to Hackernews under an assumed name, or handle, and start venting on contentious issues. Hackernews might shadow-ban your throwaway account, so you might have to lurk moar and share some interesting links before you can comment without being censored. I know from experience. Last time I checked, HN has no strict policy on multiple accounts and you can do this very easily.
In terms of OPSEC, you obviously shouldn't contaminate your real iden with your anon iden, or contaminate your anon idens with other anon idens. You should also deliberately alter the stylometry of your writing so nobody can link two pieces of text to each other. Anonymouth[0] is my favorite tool for doing just that.