I can’t think of a more small-PP thing to do than treat Social playlists (especially Action Sack FFS) like it’s the biggest and most important E-sport tournament in history.
Honestly, it’s less stressful playing Ranked than Social now, that’s how bad it’s gotten.
I think it more has to do with people who completed the cosmetic grind starting a second account, and action sack is the best playlist for PvP challenges.
Say Fat Rat loads into a game of Halo 3 on his main account. The minute that people see his gamer tag they’re gonna bail because they’d rather not get absolutely destroyed. It’s better for making content by using a spoof.
Although I don’t use smurf accounts, I understand why people do. Anyone that remotely knows how to play this game properly is a victim to the hidden MMR in system in place in the game. Every game of social for a competent human being turns into carrying three teammates either brand new to the game and with as much knowledge of Halo as a 343i employee, or a man child that is overall negative by 100,000 deaths and has Halo posters in their bedroom.
This constant need for decent players to go at least 30-2 every game in social makes the concept of using a smurf account to play casually in social more appealing. Maybe turn frustrations towards incompetent developers that would have been working on mobile games by now if it wasn’t for Microsoft leaving the franchise on life-support, instead of decent players trying to enjoy social casually like you. 
Pubstomping isn’t good content if that’s what he’s doing and people will quit out once they’re getting destroyed anyway.