Probably an unpopular opinion over here but still:

As much as I love "meme culture" and free speech, I can't help but feel that this act was influenced by those very things. I agree with what the Twitter person had to say, although not his right and left part of the argument.

The people that post edgy material on the internet might be trolls, doing those things ironically. But a lot of the times, those posts seem to have a genuine hate for a certain group. Usually I just ignore them, but for certain individuals, it can be a fuel to boost their hatred and cause them to commit crimes like these. I'm not against right wing or left wing people using the internet, just radicalised ideas in the form of edgy memes and shit that can influence a hate crime as tragic as the one that happened in NZ.