This is my philosophy on dealing with negative people online. You know, the ones who use memes and random images as their profile pics. These people almost always have something hurtful and negative to say. Realize that their negativity is, in most cases, a reflection of their own unhappy lives.
The best thing you can do is ignore it and move on. Whatever is going wrong in someone else's life isn't your problem. Focus your time and energy on yourself and the people you care about, first.