You link three things, that doesnt equate to "every independent organization". One of your links is a post by Brave and Brave isnt independent in this. The unsubstantiated fear of people for MV3 is beneficial for them, it could grow their userbase because they keep the support for MV2.
Content blocking (ad and "tracker" blocking) are convenience features, they dont foundationally improve security. Defining what a tracker is is difficult and you cant list them exhaustively. Also smart businesses and organisations can just shift to sending all data to the main domain and handling it server side to send it onwards to other domains, including third-party domains. If you dont trust a site to not send data to third party domains directly, why do you trust it to not send it indirectly?
No, I meam it restricts extensions because it does. Vouching for MV2 is like vouching for an Android OS without a proper permission model. MV3 helps against tracking, its good for privacy and security. If you want the convience of content blocking, uBlock Lite still works good enoough for many people. Though, you still lose on security and meaningful privacy (again, define a tracker and list them all, impossible) because extensions in general hurt site isolation and increase your fingerpint.