Hi, and welcome to our family!
I see you're still very young, so there's a chance you might not be completely aware of how hate crimes work (at least, I certainly hope so!), and you're probably still catching up on our LGBT history.
I read through the article you linked & looked at the photos. As an experienced driver I know it's possible for a driver to skid on a painted surface, particularly in the rain... but if it was an accidental skid then the skidmarks would've started part-way through or just after the painted surface as the tyres began to lose traction due to the paint. On the photos accompanying your article, the skidmarks start immediately before the rainbow, and they end immediately afterwards. That means they were deliberately created in that specific location.
Deliberately creating skidmarks is an act of aggression. In law, it's an assault against the LGBT community (because it threatens physical harm to us; the implication being that the driver would want to run us over). Assault is investigated by the police, irrespective of who the target is - and if it's found to have been targeted against a specific group (as appears to be the case here) then the police can and must investigate that aspect of the crime because those crimes tend to escalate to include further victims. Whoever did this was riled up about something (I think we can all guess what!) and they were angry and aggressive enough to drive recklessly. And all because of a bit of paint on a road. Or more accurately... because they violently object to the types of people who are represented by that paint.
So if they're already violent & aggressive enough to risk crashing their vehicle - and if they enjoyed the adrenaline rush it gave them - you can bet they're absolutely thrilled to see that their act of aggression has made the news. They think it gives them legendary status, and any friends of theirs who are also homophobic or transphobic will validate them & reinforce that view. So now that they're hyped up on having done that, what else are they willing to do? Would they beat up a gay couple leaving a bar? Would they sexually assault a lesbian to show her that all she needs is a 'real man'? How do you think they'd respond if they found that a woman to whom they're attracted is trans and pre-op? That's right: she'd wind up in a ditch. All of that starts with random acts of aggression such as this one.
You mentioned hate towards a city, society or country: after the last few terrorist attacks in the UK it emerged that the perpetrators were already known to the police. They had a pathological hatred of Westerners and our way of life, and they were willing to murder innocent people because of it. And it all started with smaller acts of aggression such the one you've seen over there in Saskatoon.
This is why hate crimes need to be investigated and prosecuted: because hatred tends to escalate over time and sooner or later, some innocent person will wind up hurt or killed all because of some other idiot's irrational fear. So yes, the perpetrator needs to be found & assessed to see exactly what threat he poses (and sadly, it's very likely to be a he!). People have died because of idiots who started out by doing exactly this sort of thing. Innocent lives need to be protected.
P.S. Thanks for correctly using 'purposefully'; it really grinds my gears when I see people use the non-existent 'purposely'.
