Criticism and rejection are hard to read. However, occasionally, looking through those negative comments for anything constructive can be useful. I am not saying that any of it will be useful, it might all be personal attacks. And if it is, then, of course, it's not worth listening to. But there may be something in there.
I think constructive criticism from those who are invested in your ongoing success is key to growth. However I think there's a lot of people, especially thanks to the safety of online commenting, that use the comments to simply vent their own personal issues (that are triggered by something they read). Though I also agree that it's important not to simply dismiss criticism, I think it's key to pay attention to who it's coming from.