Honestly, you shouldn't care. The internet is huge, just forget about them and their page if you don't like it.
There may be many reasons. If they are just writing informational hubs to other Christians, then you really have no place putting your opinions there. Leave them be, just like they should leave you be.
I have deleted comments before. I like to write to teach and intrigue people. If somebody comes in and starts throwing their opinions around like their opinion is the word of God, and fills my articles with negativity - you bet your ass I'm going to delete them. I want people to come in from Google, and enjoy what they read. Having a bunch of hatred in the comments isn't going to do me any good.
That said, I don't believe in God either. I have certain beliefs, and they are my own. I think Christianity is silly - but I won't go to other people's hubs and start telling them they're silly...that's just childlike trolling.