If you're concerned, just don't sub to them. Just creating communities in itself shouldn't really be a problem, I'd rather hope for the best than assume that every person making these is a power hungry basement slug.

Where are you going where you aren't required to sign a financial disclosure allowing for the relevant information to be sent to whatever service is used to collect payment? I haven't been to a single doctor's office, urgent care, or hospital in several years that didn't require me signing a form consenting to that.

Collections also doesn't need to provide an itemized list of every detail you owe for, not in the way you're implying at least. They're not about to say "you owe the hospital $20 for an aspirin." They can, however, say "you owe [this hospital] [this dollar amount] for services on [this date]." The itemization they're required to give is the current debt, any fees and interest, and any payments or credits made on it. That's straight from CFPB.