Yes, most of them are probably not "real candidates", but Google would be in even hotter water if they tried to predetermine who was and who wasn't a real candidate.
It's not up to them to decide who's real or not. It also opens up an easy to exploit situation where I can just claim to be running for president and I get some whitelist applied and could do some nefarious things.
[0]https://www.opensecrets.org/lobby/clientsum.php?id=D00006782...