That's not what the article says. The most likely situation from the article is the pilots: * disabled the trim motor * realized they were unable to trim back

That's not what the article says. The most likely situation from the article is the pilots: * disabled the trim motor * realized they were unable to trim back to level flight without it, probably due to aerodynamic load on the stabilizer * turned it back on * MCAS was still enabled -- it can't be disabled directly -- and used the trim motor itself to nose-down more, making the situation unrecoverable.