This just teaches the abusive users which behavior was caught, so they can learn to be better at evading that scrutiny in the future. It is completely counterproductive for a company to provided banned users with a detailed reason for their ban.

Spammers have plenty of ability to A/B test these things to determine which posts trigger and which don't.

Meanwhile, normal users are left totally confused, with zero recourse and potentially a loss of important data and other significant repercussions.