My mom is upset we aren't seeing her for Christmas

I'm planning on spending Christmas and Thanksgiving with my husband's family. My mom is hurt we aren't going to see her, but she treats my step kids badly. We have 4 kids in all. Mine who is 11, me and my husband's who is 3 and my step children who are 11 and 14. She doesn't hug them when we go over there or even say hi to them. My step son is pretty shy and doesn't really like talking in front of people. I told my mom this and last Thanksgiving she asked him to lead the prayer. He politely and quietly said he didn't want to, but shevtd him to do what adults asked him to do. He tried, but most 14 year olds can't come up with stuff on the spot so he just got really nervous and started stuttering and she got onto him for stuttering and scoldedhim in front of everyone and just had my brother do it. He went in the bathroom to cry and my husband had to calm him down. My mom told his 11 year old she was getting porky. My mom likes to hand out slices of her famous ham to everyone and made sure to skip them, so they just got up to get some there selves. Christmas, she wanted to take a family picture but didn't want them in the picture so none of us did a picture with her. There's just so much more and I don't feel like writing it all. She claims she doesn't treat them any different, but when your own sister is coming to comfort my step daughter because you made her cry with how rude you were to her, then that says something. She says my step son is a cry baby and my step daughter is rude. Nobody at Thanksgiving or Christmas thinks she is rude. She won't really join in on conversations unless you start them, but no one has ever said she was rude. People have said they are actually very well behaved. I told her that I'm done giving her chances every year and we aren't coming. She said just remember blood is thicker than water and some other bullshit. I don't think I'm doing anything wrong. I don't want them spending the Holidays being mistreated. Am I so wrong for that?