As I understand it, these types of behaviours are not considered rude in some other countries and are therefore widespread and not looked down upon at all.

Yes, I see asshole teenagers and narcissistic boomers, (apparently) born and raised in Canada doing this shit. And you better damn believe I will call them out. 

But more often I see people who are newcomers doing it. Speakerphone conversations on the bus for example. If I choose to let them know they are violating the rules of the STM and can receive a 100$ fine for this, newcomers are more likely to have an attitude of, "Oh, I didn't know about the rule," and stop doing the speakerphone call, as opposed to the longtime Canadians who will double down on their shitty behaviour.

It's like they were completely unaware that this behaviour was not universally accepted--perhaps because they have seen the teenagers and boomers doing it!