I think the aversion in real life to the HO is that it could easily be deadly. Besides being directly in the line of fire, you could hit the other guy. And what is the purpose of avoiding guns if you simply collide? If you hit, almost guaranteed both pilots die.
I think that real pilots would rather nix the mutual death in hopes that they could kill the other guy and get away.
HOs don't matter in the online sims because we (obviously) don't really die - thus there isn't near the impetus to avoid them.
It takes two to HO. There is also net lag to deal with that skews a tight fight and might provoke an HO just because one pilot doesn't see the other plane the way the other pilot sees his own plane. I've also had my controls get shot out where I become just a hurtling mass of metal and virtual pilot - helpless to change trajectory.
Yeah, HOs suck. But too many forget while they rant on channel 1 that they were just as much at fault as the other guy and mistakes happen. Even as much as it was avoided in WWII, it still happened and people died.