My 2 cents, having dealt with this at the EDIG hub a while back.

1. Not against the rules for a HL to flag a post and also process it as a violation. There are times a single HL might be the only one logged on at the time, and if it is an offending post in particular, plus any other rule violation, get rid of it quick.
2. If a HL makes an offensive post, flags and processes as ignore, that keeps it from being removed unless admin is notified and they do so. This is pure manipulation, against the spirit of the rules, and in the case of EDIG's board, with multiple such occurances, admin banned the HL.
3. Abusing the tools admin gives HL's to delete at will, because the view point does not fit his/her agenda, without the post violating any of the 6 rules, is also manipulation and the member should lose HL status immediately.

GLTA