Maybe, maybe not, on the 4' law. It does seem excessive, but about 10 years ago, here in Montana, a woman on a bicycle was hit in the head by one of those big wide mirrors sticking off the side of a motorhome, and she was killed. The guy driving probably thought he was giving her plenty of room, and it was probably hard to judge the far side of his motorhome and mirror.
I live along the Northern Tier route and bicyclists all summer long insist on riding on the traffic side of the white line with vehicles flying past them at 70 mph. It's nerve-wracking as a driver, even though I'm a cyclist. Part of our section only has about 1' on the outside of the white line but some of it has 6' wide paved shoulders that are pretty clean. Yet I don't see many cyclists besides myself riding out there. People around here hate bicycles.
I have a stupid daughter who rides a tandem with her 7-year old, pulling a trailer with her 5 and 2 year olds in it... in the middle of the lane of traffic in town. I'd never take that chance with my kids, and I can't get through to her that she's putting them in danger out there. People have called the police on her and written letters to the newspaper. Doesn't matter, she continues to not only be in the lane of traffic but right out in the middle of it. Whaddya do?
So regarding the comic, Yes I think it's rude toward bicyclists, and Yes I feel the frustration of drivers. I wish we had bicycle lanes in the towns around here. Though it sounds like they get misused a lot.