Core problem you come across in multiplayer team games is that there is often required support roles that are less generally desirable to play than the usual gameplay experience. E.g. people want to shoot guns rather than heal teammates.

So when you lose a team game, it's often pretty easy to look at what your team was doing, and figure it what vital support roles weren't being filled.

This can lead to what we see in the meme here, where you reflexively blame your teammates not fulfilling support obligations collectively, healing in this case. This blame assignment also purposely glosses over the fact that you were perfectly capable of identifying the problem, yet didn't switch to a support role yourself. This helps shift the blame, and absolves you of the responsibility of the loss, managing your own emotional state.

Because this helps regulate your own emotional state, it becomes reinforced behaviour, and you become reliant on it over time. You point out issues that aren't there, become hyper critical of others, anything to make sure you aren't at fault. It even goes so far as becoming reflexive at the very concept of a lost round, or any negative outcome. It's not uncommon for people to make mistakes while they're alone, and then retroactively blame their teammates for not being there with a "WHERE WAS TEAM!?!?"

In general, it's a huge problem in games like Dota or LoL. Toxicity borne from negative emotions is now part of the core gameplay experience in public matches, which leads to others doing the same. I myself can't even boot Dota anymore because of the associated negativity, despite not actively not engaging with it myself.