Various explanations offered for HR:
"Human Resources" seems to be the favorite definition.
The hand gesture itself is described as telephoning... they wouldn't be punking the opposition after a score, would they?
As if saying "These defenders are toast, y'all need new personnel, better call HR"?
(Personally, I like it. Technically it could be considered taunting, but as long as they don't do it *at* an opposing player, I wouldn't think it would be any more of an issue than a "Gig 'em" or"Hook 'em Horns" hand signal issue.
I don't know...
I do like that the Defense guys holler "ATM" at each other, meaning get "All The Money", i.e. leave nothing behind (as Hasan Defense notes, need to hold on to those almost picks, guys! )
“The world is a dangerous place to live, not because of the people who are evil but because of the people who don’t do anything about it” ~Albert Einstein