The article linked in that video's description didn't seem to exist. But doing a little digging, I saw Backstreet going on record, (around the time that video was made), and saying nothing happened to them. Nick Carter was iffy sounding but the group did say that they were the manager's first group so they missed any thing like that but heard it may have happened to the many acts signed after them.
I also saw Lance Bass say that he felt uncomfortable about their manager but never experienced any sexual abuse or harassment. And this was around the time his book came out, again, the same year as the video and Backstreet article.
Sounds like something did happen and either it wasn't to them or they're not keen to discuss it. Still not seeing any explicit source saying either group experienced these things. But I do see many allegations regarding other groups under the same manager.