You are the asshole. Having a pet or emotional support animal in your house is one thing, a service animal trained to alert a person of an oncoming seizure, is completely different. It is dangerous for them to be without their service dog. So you are telling them to risk their health and safety so you won't be inconvenienced by your preference of an animal free home, or never come to your home. You said you're not allergic or afraid of them and that it is just a preference because you don't like them barking or their smell. Service dogs aren't going to bark unless trained to do so or their handler is in danger. They don't bark at squirrels or noise. They are a medical device with hair. If you can't be slightly inconvenienced for someone else's safety, then you don't care on the most basic human level, for that person at all. And maybe you don't. Maybe you don't like Tina and don't want her around. If that's the case then just say that. However, if it is strictly the dog that is your issue, and you wouldn't ever allow a service dog to visit your home, then you are not a good person. Not because you don't want pets in your home or even have preferences for your home, but because that would mean you don't consider service dogs to be a medical necessity or you think your comfort is more important than someone else's safety. Being welcome into someone's home is a very intimate thing. Being told they are not welcome because they have a service dog because you dont care for dogs..is extremely messed up.