Yes.

Yes, and there's nothing mixed about the messaging. If you know what you're doing, go ahead. If you don't, dont.

Usually compsnies would just say no to everyone and throw around words like "unauthorized".

You underestimate how stupid the average person is.

Product specifications are different for the parts accessible to a user and the parts not accessible to the user.

If you tell a user "you can take it apart" the user will believe the product was made with taking it apart in mind. But it was not.

For example, a toy that is made to be taken apart, like legos, will survive it being taking apart thousands of times. But an electronic device that was made to take it apart only for repair purposes may last only tens of cycles.

So if a user disassembles their controller 100 times, a part will probably break, and the user will complain about it being such bad quality that it broke after taking it apart "a few times".

That's why it is important to disclose what you are MEANT to do as opposed to what you technically CAN do.

Then why are you so butthurt about this?

"Your house and electrical wiring is yours, and you have the right to do with it what you want. That said, we highly recommend you leave it to professionals."

This is not mixed messaging, this is just advice. Mixed messaging would be something along the lines of: "Your house and electrical wiring is yours, and you have the right to do with it what you want. That said, you are not allowed to do what you want." Mixed messaging colloquially means contradictory statements.

You're grossly overestimating the competency of the general public

I didn't expect changing an SSD to be such a technical task for you.... I mourn your lego-less youth.

For a screen or CPU replacement, yes. For memory, no. Gotta break what's not broken to fix something.