"Authenticating themselves" to who? This, to me, is just another way of saying "residential users must use an approved sender and can't send mail themselves" since residential users will statistically never be able to get PTRs changed to their domain and instead will have to deal with them pointing to the ISP.
It's another way to force people to use the handful of approved providers to send mail and it's really shitty.
My archiving account was also disabled on April 1 and all my history deleted, despite the fact that it was paid through sometime in 2023. I also got no renewal notification like I had every previous time the service expired.
I didn't bother contacting support because I've been ignored for the past 2 months in my repeated inquiries about archiving being broken, so I just accepted my money being stolen.
Seriously.
https://en.wikipedia.org/wiki/Wickard_v._Filburn