Pair programming should be optional and for whoever wants to get team members (especially juniors) up to speed and on the same page. It could be very productive but like all methods/tools that are shoved down everyone's throat and forced to apply them, I could see them being a disaster.

I generally enjoy pair programming when utilized occasionally and as needed, but mandatory pairing is just horrible.

Each tool has its use case. Forced use results in misuse.

I actually found it quite helpful, not just for getting up to speed. After moving to another division of that company that didn't employ full-time pair programming, I saw code of noticeably lower quality being produced. That said, it was emotionally exhausting for me to do full-time pairing and I'm not sure I'd go back to it.