I will try to answer your question "Is there any correlation between reputation and the politeness" based on my experience on this network and what I have read from other users.
You might see that I am myself quite new to this network. Although I used Stack Overflow as a developer I did not register here until a bit less than two years ago. Also I was one of the few new users who read most of the rules before they do any action on the site. This is both personal interest and something that seems normal for me. These factors might have caused me to mainly participate in this very meta site for the last months.
Now to answer your question. I think it depends on what you call politeness. Most more experienced users expect high quality standards and try to enforce the rules because they think that these sites serve a long-term goal. They are opposed by users that think that this site is their personal help center. Both parties are in an
eternal struggle. One group tries to keep the site clean and the other party wants their answer as soon as possible.
You can read more about these groups here
Now let's look what each party says in which the other one is impolite.
The "need-an-answer"-users think that everything and everyone that prevents them from receiving an answer as soon as possible is evil. When someone criticizes them for not posting enough details, they think this is rude.
On the other hand we have the "care takers". These users think that it is impolite to the whole collective work thousands of people have done before to produce low-quality content. They use the moderation abilities (voting, flagging, editing, closing) to try to maintain a high quality.
Unfortunately downvoting without explaining what is wrong is perceived rude by the members of the first group. But so is commenting with improvements. This means we can't satisfy everyones dreams.
I am not saying that members of the second group are never snarky or unfriendly!
So when you want to measure politeness using comment deletion statistics you have three problems:
- Moderators will probably delete borderline comments that have been flagged by new users because of the welcoming project.
- The rudeness of the first group ("low-quality content") can't be measured using this method.
- Active (high reputation users) produce more content than newer users. when one comment of five is rude/abusive this means something completely different than when 1 of 10000 is rude/abusive.
Therfore any comment-deletion-based statistic is bound to be biased against the "care takers".
If you want to look for other statistics, I don't think you have any. It is probably really seldom that a high-rep user posts a rant on the site. But except for deletion reasons (rude/abusive vs. normal) you have absolutely no data for this, at least I can't think of any. You could try to search for certain keywords using SEDE but this would only result in a small amount of possible resuls
You might have noticed that I am (slightly) prejudiced towards the second group. Therefore don't take any points from this answer as universal truth.
But it is a fact that high-reputation users produce more high-quality content (with occasional outliers on both ends) and in the end it depends on what you want:
- yet another forum where users ask any questions they want and no quality enforcement, or
- a site with searchable high-quality content.