@jb55 IIRC there are several aspects:
1. Scales employed aren't dichotomic
2. Four-letter results are unstable: tests are unreproducible in a non-trivial amount of cases.
#SGU had an OK coverage, as well as a wondefully-written article in some newsletter of a psychology journal.
I think that what annoys people the most about MBTI is that it became an industry that sells the very same product eugenics used to sell.
Same thing with mindfulness. I'm the first to defend the subjective positive effects of meditation and subjective joy of naturalistic Buddhism. But when a harmless (and maybe helpful) hobby starts to get aggressively marketed to a degree when *individual* fake gurus make millions a year, scientific community absolutely has to make a stance.