Well when you break down a code of conduct, it boils down to these three issues -
1. Moral issues (eg, afk dilith farming)
2. Social/behavioral issues (eg, rage quitting/trash talking)
3. Knowledge issue (eg, what is cheese?)
Especially in light of how easy it has been to farm space STFs recently, the moral issue (afk farming) should not be a problem. Moreover, I have been told that there are 'channels' that are created to address this very issue. Maybe such people should be pointed towards those directions. They value efficiency, right?
Social/behavioral issues are something that can only be addressed with a positive peer pressure. No matter how much logical and well-reasoned argument or explanation, somebody who does not care about who you are, is obviously not going to listen to you. If somebody is your friend or is in your fleet, then it is your responsibility to guide them. If you are in this thread, giving it a read, you are probably the person who can be that positive peer pressure.
A lot of times, the social/behavioral issues stem directly from knowledge issue. Nobody likes to lose. Nobody likes to die. Everybody likes to think they are smart. And when they take a build, that according to them should perform very well in any condition, into pvp and they suddenly have a harsh cold reality thrown at their face, they might lash out due to frustration. Accusations of hacking and cheatings are thrown around, and when this does not satisfy, at the very least, the opposing guy is surely loaded with cheese. The only way to mitigate a knowledge issue is to actively help them understand why a cheese is a cheese. Sometimes you succeed, sometimes they rage on you and put you on ignore list. But at least you tried, right?