Does his stepmom have the right to be upset?

I think the only thing my ex's new wife cares about is money. She was on her myspace griping that her state taxes went to my husband's back child support and she was mad about it. Then today, she was griping that the tax preparer messed up on their taxes and they won't get them for awhile and someone commented and she replied back saying that she has to file a special way so that her taxes don't go to me and that she shouldn't have to pay for a child she didn't create. Why can't she shut up and put my son and his needs first before her stupid fat *** and money? I think it's funny her taxes go to me, she knew what she was getting into by getting with my ex, I have no sympathy for her. I think she is being selfish and when I texted my ex tellign him I thought his wife was being selfish, he called and yelled at me and started a big fight between us. Does she have any right to be upset? I think she's just being stupid.