It does seem so, yes, but I think a combined effort from the community, developers and online services to punish toxic players and reward teamplay and friendly competition can go a long way.
Just take a look at classic Counter-Strike or Battlefield 2 and compare it to modern online shooters. In the former, winning a match was the center of gameplay which put focus on teamplay and team efforts. There's also little to no long-term effect of winning or losing.
In Battlefield 3/4 or CoD, your personal profile is the center of your attention. It's about levelling up, achieving high scores in a match to unlock new stuff. Which leads to lone wolf behavior and aggression towards all who hamper your progress. Likewise if you're just in it for the bullshit, you wouldn't get called out for it, because no one really cares about how the team fares anyway.
In the same way, game design focussed on rewarding you, personally, and making you feel like you're special with constant pop-ups about your great achievements and deviated from teamplay, communities became more hostile and the arrogance of good players prospered. Of course, it's not the only factor in that process, but it plays a role, and developers should have an eye on that.
Other factors, obviously, are the anonymity and lack of consequences for bad behaviour, making it an ideal vent. So, systems need to be in place that make sure punishment is an option. And it should be more diverse and direct than the classic (timed) ban/kick. We already see first tests of that, with what I mentioned above: exclusion from certain game modes or making reputation a part of the matchmaking algorithm, etc. It's about time.
Straying pretty far from the topic, I'm afraid.