But it shouldn't. If the steel was processed properly, and it's magnacut, it shouldn't have stained so easily, if at all. If it stays away, the DLT's claims are legitimate and BRK looks like a lazy maker show either skipped a process or are trying to save money by not switching belts, again, assuming that's what really happens.
If it cleans the stains and they come back, then there's something else going on. Maybe it's poor heat treatment, maybe it's the wrong steel. Either way, BRK is messing something up on a bigger degree than just using dirty belts.
A much less stain resistant stainless steel can manage to stay stain free, magnacut should be able to as well. The data is there for BRK to follow on heat treat along with the test results on it's performance for corrosion resistance.
Objectively, it should not stain so quickly. From the OP's pictures, I've had a harder time getting something like M4 or 3V to stain than he did magnacut, an actual stainless steel. Heck, my whole kitchen knife set is carbon steel blades because I like patina, but if I have a stainless steel blade of any kind and it stains faster than my blue #2 kitchen knives, things are not as they should be.