I've had a dim view of them ever since my first interaction with Domains by Proxy (At the time, I recall finding that many 'windows support' scam sites and other malware distribution was showing up under their domains, and every attempt to uncover would only lead to a 'oh that account is now banned but we wont tell you thx'.)

... Honestly it reminds me of how some Internet VOIP providers won't tell the name of the business who actually bought the number (Which, of course, complicates the ability to collect on TCPA when it's a number used for spam.)