1. MBAs are useless, and should be ignored
2. MBAs are useless, and are ignored
On the first point, I don't think MBAs are useless, and in many fields, as the field becomes technical, the MBA becomes more useful. Marketing is more technical, operations are more technical, finance is more technical, and the MBA provides a sort of intro like getting a general medical degree before specializing.
It is true that a candidate should be judged on their merits and a non-credentialed candidate in any field may be superior to a credentialed candidate. That is a more general point about credentials. The counter-point is, how do you find such a candidate? If I interviewed 5000 people, perhaps the best one would not have a particular credential, but if being human I can only interview 20 then my chances of finding a good candidate are higher if I focus on the 100 or so credentialed candidates in the batch. In short, the credential provides some signal.
Finally, even if were useless, it doesn't appear that they are being ignored. Hiring is still strong, and salaries are only going up.