I've been thinking, and I've come to the conclusion that it is almost always better to ignore a post on the internet than to spend time arguing with it. It can be for big things or little things. Either way, if you're not going to match the post's energy, then nothing worthwhile will come from engaging with it.
For instance, if a post is venting about a book or show that you really like, its original author is probably not interested in hearing about how you just really enjoyed it and people who are frustrated with it are meanies and haters. (Or, since it's the internet, accusing them of being the root cause of all the world's problems.) Similarly, coming onto people's posts and telling them how stupid they are for liking a thing you hate is obnoxious too. Even if they're talking about things you deeply disapprove of, you are not going to teach them a lesson on the internet.
Granted, it's probably foolish to be posting this on the internet, but I'm not tacking it onto someone else's thing. I'm just posting it on my own Tumblr blog. I just see how you really have no idea what kind of space a person is in on the other end of the information super highway, and although our brains are primed to respond to aggravating stimuli, very little good ever comes from stirring up conflict on the internet.
It's not that the internet isn't real. It obviously is. At the same time, it offers immediate connection to basically any random person you'd like with next to no context. Unless you know a person personally (like, you have each other's phone numbers and have spent time together in-person before), you have no business picking a fight with them on the internet. And, if you do know a person personally, the least you can do is have your fight somewhere OTHER than the public internet.
Side Note: Obviously, there are various forums on the internet where arguments and debates are literally the point. Those aren't what I'm talking about in this post. I'm talking about a site like Tumblr or Instagram or whatever, where people are just posting stuff for literally any random reason. Those venues do not require you to give your two cents. You can move on. Sharing stuff on the internet actually isn't an invitation for you to give direct feedback and criticism, nor to conjure up a dogpile on random people you disagree with.