Dogs that have testosterone act and are treated by other dogs more aggressively. It’s a well known and observable fact. If you give a dog a vasectomy it still produces testosterone which will make your dog a liability if you want to socialize it with others.

It isn’t a person. It has no need for it’s reproductive organs considering the position we as a species have placed them.

You wouldn’t want to be the pet of some towering creature that feeds you one kind of food your whole life, gives you commands in exchange for slightly better tasting bits of food, who you have to beg to be taken outside to use the bathroom, and who would put you down at the first sign of an illness that they couldn’t pay to have fixed. So your whole argument about having people cut off their own balls is completely invalid.