Bullsh*t! A 50 cal is as useless against a tank a 100 yards as a spitwad, much less a mile.
Probably depends on how loosely one defines a tank. It would be useful against a PTR, or BTR, or for that matter an M113 or even a Stryker. Even the rear or top armor of some true tanks.
But of course these Bozos are just repeating whatever slop they hear from the Brady Bunch.
Not necessarily. The TC sticking his head out of the turret generally makes an easy target, and would no doubt have negative effect on the outcome of a shoot out, not to mention the crews moral.