Yes, this is true.
Meh, it really depends on the type of stop and conditions.
Regardless of the number of wheels one's preferred mode of transportation has I'm not gonna complain about people doing rolling stops at 4-way stops where there's good visibility and the traffic conditions are such that there's no possibility of misinterpreting who's turn it is or at a right turn that would be a yield instead of a stop were there not a left turn option.
I disagree. A stop sign is a stop sign. Otherwise the sign would say use-your-judgment-and-decide-what-to-do.
Huge numbers of stop signs are found in North America, but they're not so common elsewhere. In Europe, most smaller junctions in residential areas will have a "yield" sign, or no sign at all. Busier ones might have a mini-roundabout (give way to the left).
In the UK, installing a stop sign requires the permission of the central government. This is to keep the sign special — if you see one, there really is some risky road layout that means you can't see safely until you're stopped at the sign. There was only one example anywhere near where I grew up: next to an junction by an ancient castle where parts of the building overhung the road, meaning large vehicles might be on the wrong side of the road to pass by.
If a car is travelling at 35 mph and you're traveling at 25 mph, then the relative speed of the car is 10 mph.
If a car is travelling at 35 mph and you're travelling at 10 mph, then the relative speed of the car is 25 mph, which is going to hurt a hell of a lot more than being hit by a car travelling 10 mph relative to you.
The same is true of bicyclists who do the same.
I have never driven a car in my life (age 35 currently) despite growing up in a very rural area. Now I live in a city and bike everywhere and NEVER run a stop sign. The behavior of both drivers and bicyclists is embarrassing.