Why is it a Violation to ask someone to report an answer or question so that it can be deleted?

You are always free to solicit reporting help via contacting users directly, which is to say, those users who provide a way of contacting them. Depending on the nature of the violations you are concerned about, you might find allies at the Chatzy site mentioned on the suggestion board, and there are also ways to get the attention of members of the Y!A Team who can get people suspended for persistent violations.

But soliciting reporting help in the form of questions and/or answers has the result of further cluttering the site with content that is not informational Q/A. That's a fundamental rule; it is, and in my opinion should be, enforced regardless of good intentions.

-- edit -- Checking your profile, I see you participate in the Football section, and you're right, there is a lot of abuse there. The reputation of that section is that many of its abusive users are using multiple accounts to troll, point game, etc. All the more reason to show suspicious accounts to someone on Y!AT. email: y_answrs_team@yahoo.com ('answrs' is not a typo). They have ways of tracing such things down. Good luck.

Presumably the designers of the rules were well aware of the potential for drama and escalating hostility if users were allowed to publically 'call out' others (bearing in mind that such requests might be malicious).

It is considered a "call out".

You need to either increase your Trust Rating or develop a network of friends who will report along with you.