Am I wrong for being this angry?

My 3 year old little girl has sensory processing disorder so she's not the easiest to deal with but were getting there. We went over to my brothers house who has 2 children, girl and boy Ages 3 1/2 and 2Now their 3 year old little girl is very smart and Aticular for her age while our daughter acts more like a 2 year old sometimes. I literally dread going there because our children don't see eye to eye and they're always fighting over something. Plus they always act like it's my little girls fault when in fact half the time it's their little girl who's bullying my daughterCut a long story short, my little girl had some toys that she brought over from home and Allison (not real name) decided she wanted to play with her. Now this is how it always starts. So Ann let's her play and shares her toys with her. Then after Allison's done playing with Ann she'll go and get her own toy (I know she does this on purpose it's happened several times) and doesn't let my daughter play with it and taunts her. My daughter then goes into tantrum mode and everyone is like oh you're daughters so bad.Then while I was trying to console her and get her tantrum to stop their little boy took her bubbles and spilt them all over the floor. She went wild after that and ran towards him and knocked him down. Then my husband grabbed our daughter and spanked her which created a big argument between him and I. I didn't want to undermine him but I've told him several times I don't condone in spanking and that's not how we're going to raise our daughter.Now I'm home and I've been crying and really upset at how my daughter gets treated and I've promised myself I'm not going there anymore.As for my husband I can't seem to get him on the same page as to how I want us to raise her and it's causing so many arguments. I'm so angry at the way my daughter gets treated when at my brothers house and the mom and dad act like my little girl is the problem cause she has sensory issue's when in fact it's their shitty parenting. If I ever do decide to go back there I swear I'm not gonna let my daughter share any of her toys. I know it doesn't make it right but screw them. I'm just so angry right now via /r/Parenting http://ift.tt/2uFhy9D