It's probably like when people have kids and their kids are complete monsters but they'll talk about someone elses kid being like that right? So on the one hand, it is their house and they have a right to ask you to take Xander home, especially if he was acting aggressive towards her (even if he doesn't normally), but on the other it's weird that their dog is aggressive and in need of training yet, it's ok for him to be around their son

Sadly as sweet as Xander may be, he still acted aggressively, and that will need to be addressed, regardless of whether it was the meat he smelled or if he just didn't like this lady. I can understand you being upset but I would consider the opposite situation where if they brought their dog over, you would probably ask them to take him home. I would be upset too, but don't worry no one will consider him the aggressive dog on the block, cause they will all see how sweet he is for themselves. That is a the sweetest picture ever!