This is actually the opposite of what the post says.
The subtext here is that cretinism is acceptable, but being a target is not. If you’re a total dick who only uses the Internet to seek out strangers and ruin their day for kicks, you are absolutely welcome. If you happen to be one such sought-out person, there’s the door. What kind of reasoning is that, and what kind of society does anyone think it’s going to create?
That is a paragraph from later in the article.
People seldom take perspective and context in account. Especially if they all go into the angry mob mentality as you mention which I'm pretty sure we have seen plenty of times.
Part of the problem is the speed that the Internet affords us. People feel the need/urge to respond to things instantly, which often prevents them from taking a breath to get some perspective or maybe to even do some fact checking.