Not going to downvote, but tempting as you don't seem to be looking for answers, rather just arguing position sans care for evidence.
However.
1st question, I think ashe supp taking CS might be bannable. The reason "off meta" is sometimes banned is that it puts you team at a disadvantage if they aren't made aware of it first thing in champ select. Champ picks, rune set up, etc are made with certain expectations. The "no one's CS" statement is usually in reponse to an adc complaining about a support taking ANY cs. It's a little more sketchy when the support is actively CSing (especially since some of the support starting items punish you for CS).
There's no concrete statement from Riot concerning what is bannable in terms of "off meta". They only recommend that if you think your strategy may require explanation that you do so first thing in champ select. Likewise, if you say your intentions and the team disagrees, and you still so it, this may become punishable.
Lastly, to the Nubrac situation. He didn't communicate his intentions in champ select or if he did he disregarded team feedback. Riot also found that his "off meta" picks had a high correlation to if a streamer was present in game. If one was, he tended to do "off meta".
The noncordination, coupled with the attention seeking attempts to rile up streamers, is what lead to punishment.
Edit: Should have read further as others covered Nubrac.