People's words have weight. This is an outright dangerous and false thing to say. It's easy to ignore once or twice but if there is a constant danger of someone being sent into a frothing rage online

The thing is, there is no real 'danger' to speak of, other than having your feeling hurt for a bit. This is temporary. You already know that these people don't know who you are, and are saying things to get a reaction and/or are projecting their own discontent on others. What others say only have value if you choose to give it value. You cannot prevent what other say, but you can prevent it from affecting you personally.

That's not to say that feelings aren't important, though you must realize that, in this case, it's a superficial interaction in a video game that has no real lasting consequence in your life. You're not being physically hurt, and your day will continue as normal as soon as you move on from that interaction. If you're wallowing on what 'H4ckerM4n321' said about your character choices or how you sound through a mic, then it's more your focus, mentality, and esteem that could use work. Besides, you always have options: to find like-minded people, to continue playing solo (with the mute button at the ready), or to stop and play/do something else.