This is a hard question to answer. I, personally, don't think that "formula" feeding mom's are mean. And shouldn't be labeled as one kind of mother, either. I bottle feed my baby, and I know the benefits of breastfeeding as well as anyone. And my decision wasn't because I thought it would easier, or that I was just a selfish mother. When you choose to do something, it has to make YOU happy in order to make your child happy. And for some people, breastfeeding just isn't enjoyable. I know that some breastfeeding mommy's couldn't imagine that, and for that, your lucky. But, it doesn't mean that were second-class mothers.
I am not an inadequate mother, and I don't think how you choose to feed your child determines how you are as a parent in the long run. When your child enters kindergarten, are they going to love you because you breastfed, or because you stayed in the parking lot, just so they wouldn't be alone?
There are some mean-spirited posts about breastfeeding, and there are some mean-spirited ones about formula. And if you notice, most of these posts are from pretty much the same people. So, it isn't fair to bunch mother's into groups. When I meet new mothers, how they feed their child is never a question I ask. Because it doesn't define you as a mother.