Who said there was something unusual about it?

Because it's every normal person's boundary to protect themselves from those who stalk them. Again, driving once doesn't qualify as stalking, but if it becomes a regular occurrence, that does fall under the definition of stalking and if you are a victim of it, you have the right not only to end the relationship but to report this behavior to the police and ask for a restraining order. If you wouldn't do that, that's fine, that's your choice, but many people would, therapists or not, and they have the right to do that.

As to the rest of your post that speaks about the comparison, the bottom line is that it is culturally acceptable in this day and age to google people and it's not considered stalking, but regular appearance next to someone's house does fall under the definition of stalking, which is an unlawful behavior that could get the stalker in trouble. Like it or hate it, this is our reality. Your opinion will not change the current law and the current cultural norm. This norm may or may not change in the future, that I don't know, but today it is what it is regardless of what you think of it.