Why are people so judgmental about dog owners?

Not that I have a dog or anything, but I've been wondering about this. When I was younger, I always thought dogs were haram. From what I've learned, it's not the dog itself that's considered an issue but its saliva. If you keep the dog out of the room where you have separate clothes for prayer, make wudu there, and pray in that space, then it's valid.

That said, there is a hadith that says angels do not enter a home where there is a dog, so you would miss out on that blessing.

Yet somehow people go crazy when they see a muslim (especially hijabis) with a dog. Is this ignorance or not?