Uh oh. Thanks for posting. Were the closures mostly recent? I can only see OP's post but not the timestamps of those he quoted.
The closures are all today. To give some context, it seems like people doing very high volume (one poster speaks of $5k in rewards for multiple months and owing ~400k on the card) are the subject of the shutdowns. I'm hoping that my $5-10k/month flies under the radar.
I was on the phone with CS adding authorized users a couple of ours ago, so as of then my account is normal.