U.S. people are better at that game, since it is expected and rewarded in work life. This is also why they push for CoCs, which have nothing to do with manners or niceness, but are just another power tool.
I have never seen a genuinely nice person push for a CoC. Not once.
What I just considered due to your post is that it's quite likely that those who support C.o.C.s are also more likely to cast votes.
I think it quite likely that those with a libertarian life philosophy are far less likely to cast votes on websites in general, especially to voice disagreement.
I concur that those who want enforced niceness seldom are nice themselves and tend to often have their reasons and excuses of why they are justified when they are not so nice.
The use of CoC might be one of them.
The zero tolerance politician with a domestic violence conviction probably believes that in his case it was different and justified, just as everyone with a domestic violence conviction does.
It seems to be a common thing that those that demand the strictest morality rules also seem to have the most aggression problems and often overstep their own rules, but typically have an excuse ready why in their case it's different.
Though, perhaps it simply stands out more if it's one to chant “code of conduct” or “zero tolerance”, but as far as statistics in the Dutch parliament goes, it's often pointed out that all the parties that are in favor of lighter punishments and rehabilitation tend to be spot free, whereas politicians of parties that advocate harsh punishments and zero tolerance tend to very often have past criminal records themselves.