It may be that people's resistance to joining a group drastically increases if the group fails any one of several criteria.

Maybe, but I don't know how we'd know the difference.

The level of abuse done by bosses and cult leaders is different, so although the statement is literally true for both bosses and cult leaders, it really doesn't imply that the two situations are similar.

Is it really? Remember how many thousands of NRMs there are over the decades, and how people tend to discuss repeatedly a few salient examples like Scientology. Can we really compare that favorably regular bosses with religious figures? Aside from the Catholic Church scandal (with its counterparts among other closemouthed groups like Jewish and Amish communities), we see plenty of sexual scandals in other places like the military (the Tailhook scandal as the classic example, but there's plenty of recent statistics on sexual assault in the military, often enabled by the hierarchy).