Me and others have seen idiots riding literally on the car lanes in busy major roads.
If more idiots continue like this it will be an issue fast.
As a cylist, you are entitled to use the road. So long as you remain in the left lane, there is nothing wrong with it.
We cant always stick to the quiet back roads, or bike lanes, some of us actually ride ourbikes to work, where there is no alternative at times to the types of roads you describe. If there is no bike lane, I'm going to take a car lane. This is the safest thing for me. It forces the cars to overtake you properly, rather than trying to squeeze past you.
Of the commute I do every day on the bike, approximately 1.5km of about 4 -5 km is on a busy major road. There is no alternative for me. So long as your not riding lie an idiot, going too fast, wearing your helmet, then there is no problem. I have ridden past several police with the engine running, and they didnt even look twice a me on those roads. Obey the road rules, and you in most cases will be fine.
I have even stopped next to a police car at the lights, they looked me and the bike up and down, nodded, then drove off when the lights changed. This was on the "busy Major Road" that according to you I am an idiot for being on.
My point is, ride safely, wear the gear you should be wearing, dont act like a tool on the road, obey the road rules, ie stop signs, traffic lights etc, or go faster than you should, and there wont be a problem.