Sounds like typical "billy big rigger" schoolyard stupidity to me. Maybe the ones who are driving the slow/ legal trucks are the ones who laugh when they see the fat paychecks they get by being safe, while the "cluck cluck chromed up chicken truck" crowd sits in the truck stops because a. Their company's Csa scores are so lousy from running 2-3 logbooks or falsified Elogs that no one wants to put their product on their chromed up trailers, or b. some people can't get it through their thick skulls that the days of "smokey & the bandit" are (thankfully) over with.
By the way.... Maybe you should consider that some of these "slow poke too skeered to drive fast rookies" May be ex- military, possibly just back from Iraq or Afghanistan, started a new career, and have seen more terror - inflicting situations in the battlefield that would make some of you "fast truck cowboys" cower in fear.