I sent a screenshot to PD. They said they were previously unaware of the issue. Shutting down customer access without a plan is pretty silly.
Hopefully we have a resolution soon.
Private Division updated their support page for KSP 1 and 2 downloads sometime in the last 11 hours.
https://support.privatedivision.com/hc/en-us/articles/360037744353--Kerbal-Space-Program-Can-no-longer-access-my-KSP-1-and-KSP-2-download-links