SF1900 is 100% correct on this issue. Anyone who disagrees with him has either never driven in actual fast, busy traffic or is a bad driver or just an asshole, or some combination of these things.
The law in America is simple: you go at or below the speed limit unless it's unsafe to do so based on the road conditions or flow of traffic. The flow of traffic is never 20+ mph over the speed limit, so if you're going 80 in a 55 and want everyone else to move to the right and get out of your way, you're the problem, not them. "But I'm late for my minimum-wage manual-labor job" Tough shit, should have left sooner. "But my fat wife is giving birth again" Tough shit here too, the rest of the road isn't obligated to drive unsafely because of your personal situation.
The speed limit on my commute is 55 and I usually go 60-65 along with most of the rest of the traffic, which is very high-volume. If some asshole wants to go 75+ then it's their responsibility to operate their vehicle safely under those conditions. It's not my responsibility to accommodate them and shift out of the way, cut someone off at speeds that will cause major damage, injuries, or death if there's an accident. If you drive like that it's just a matter of time and number of exposures until you kill yourself or someone else. Drive on the shoulder and tell the cop you're on your way to the hospital when he pulls you over if it's really such a dire emergency.