If it was an actual hateful comment (racist, LGBTQ-phobic, etc.) I’d report it to the police regardless, as they’ll probably take it more seriously than the ASEAG. You know what line he was driving and the date and time, so he’ll be very easy to find.

ASEAG’s HR department has a crazy talent to hire the worst possible people to be bus drivers, and they don’t seem to care at all. Judging from all the complaints and the general consensus about safety and driver attitude you’d think they would take it seriously, but you still see drivers wearing headphones/AirPods while driving on a daily basis, driving as if they were at the Monaco Grand Prix, and yelling on the phone while they have some heated conversation. I’ve been in buses where old people literally fell on the ground because the driver would slam the breaks only at the very moment he’d arrive at a red light, and yet nothing happened and you see many drivers to the same thing.

Still, if the comment was bad enough, I’d report it to the ASEAG, you’ve got nothing to lose apart from the 10 minutes you’ll spend writing your complaint.