Anything public in the internet or allow anyone signup is scraped-able, or sellable.

If you want a true private Lemmy, then meet some real life friends, host your own forum that only allow friends read stuff.

Think of the problem being solved. The Fediverse solves multiple problems, but most notably ensuring that our contributions won’t be paywalled by some corporate grifter. The post and comment data itself is free and open, subject only to TOS and regional legislation.

If you consider your conversations valuable, stick with something like secure messaging application groups. And then hope nobody in that group does what you imagine in your second point.

2 downvotes less than a min, you haters better leave an explanation.