[younata]

  > The issue isn't "word choice" it is tone and writing style.

Forgive me, my vocabulary failed me when I was writing that particular sentence.

  > Writing in leetspeek is equally objectionable, for instance, and people do downvote those who write that way on HN.

Good point, although leetspeak kills readability, whereas "this." is just a way to say "yes, I agree with you.".

In my opinion, a comment that is simply "this." should get no votes at all, whereas a comment that is entirely in leetspeak should be downvoted into oblivion. Killing readability is a far greater sin than simply failing to realize that the upvote button exists for a reason.