I'm not sure it's creditable that enough credence is being given to these anonymous claims in a private group to be impacting this person's life. Seems more akin to a slapp.
People who wish to mask their crimes have a greater incentive to use E2EE so will probably gravitate towards platforms that offer it. I would therefore suggest those not committing crimes are disproportionately affected by E2EE not being made the default where possible. Once one service in a particular category offers E2EE, the benefits of the other services in that category not offering it is significantly reduced.
One thing you might want to consider is having one domain for a website about collectednotes (collectednotes.com) and another for hosting user's blogs (collectednotes.blog for example) because it is currently not clear what urls are official and made by you and which are just blogs made by anyone.
Is the extent of the 'unlimited' important? Lending a single book more than they own is an impossibility if they are respecting IP - no different to a physical library photocopying entire books so they can lend more.
Oh let me see, perhaps it has something to do with China being a one-party state with a ripe history of human rights atrocities and pervasive censorship.
Just look at SARS for an example of where trusting the official information from China made for a terrible idea.
I'd say you were a lucky one. Persuading my contacts to move and explaining my rationale has been a long, arduous and still not quite complete process. People seem to struggle with envisaging how a lack of privacy will harm them personally.