OP is a professional dog walker who visits an apartment complex in a busy downtown area every weekday
The section is marked with signs saying "Future Resident Parking," and the rest of the small side road is marked with "No Parking" and "Ticketing and Towing Enforced" signs.
The car in question is a black Ford Mustang with a handicap sign
The car is parked in the spot at least 3 out of 5 days OP visits and it bothers them.
This causes OP to waste time driving around the busy downtown area to find a parking spot or risk parking in the no-parking sections, thus making them fall behind schedule for the rest of their walks
So, OP asks if he should complain about the car.
OP has offered the following explanation for why they think they might be the a-hole:
It's one spot.
The car there has a handicap placard.
"They have a handicap tag. If anyone, they get first choice on convenient parking."
Not your apt - no right to complain
"It's a large SINGLE space. NOT 2 separate spaces"
The bottom line is:
Yes, people can sometimes go overboard in a fight for a parking space. However, it is important to remember that it is only a parking space, and it is not worth getting involved in an altercation.
The car in question has a handicap sign and should be tolerated. OP should definitely lighten up.
If the building management tolerates the car, we can't really understand why OP feels they should do something about the car.