You know? I have been thinking about this too... I was used to have my opinion ignored, that changed when some people started to ask me about my opinion on facebook, but that was for one niche and I consider myself good at it.
But now, someone like me can voice his opinion to the whole world. And once I have done that, it is out there forever. No one has trained me for this or explained the risks but I am on an international stage.
What if I do get noticed?!? And what if I get noticed for the wrong reasons?!?
It drives fear when you think about it that way, be a good person... Then even if you were attacked, people won't be happy about it.
Funny thing is, all the points of advice you mentioned are things I already do by instinct from the beginning... Though I think I'm guilty of things you haven't mentioned.