What's the difference between a stranger on the internet yelling at you versus a crazy homeless man in San Francisco yelling at you? Absolutely none, their thoughts affect in you in 0 ways, feel free to ignore and carry on with your day.
Edit, because a lot of replies are getting off-track: I'd be curious to learn if it is different in open-source and if so, why. My understanding was that the "professional" way to deal with hecklers online is in fact to ignore them and delete/block their content.