share non-purchased iCloud music

You don't.

None of Apple's iCloud Music Library services provide a way for you to share music where Apple did not provide you the right to share.

iTunes purchased music comes with that right as allowed by the copyright holder(s). Music you have sourced elsewhere may not.

I have the right to share purchased music within my household. I have the right to make archival copies of purchased music.

Not via Apple, which is my point. Your question asked about non Apple sourced music.

Apple does not block you from doing as you please with your non Apple sourced music. They just don't provide the mechanism to do this.

Apple wants users to purchase content from Apple and discourage users from adding content they have purchased elsewhere.

It's all about rights. Your anger belongs to the right holders who determine how their product is consumed.

Apple wants users to purchase content from Apple

Of course they do.

So now I don't understand the point of your original question.

You came back seeming to have insider knowledge that Apple is able to allow this sharing but chooses not to.

Fair (and unofficial) warning... this type of conversation is not suitable for this community. We volunteers answer technical questions. Discussions about Apple policy and decisions is not allowed per the terms of the community. Their yard, their rules.