The freedom of Hive means you can downvote for your own reasons, but the posts will still be there. Someone could make a front end that ignores downvotes. There is this that shows who has been hit the most.
We get plenty of feuds here. Some big accounts can expect to have any post sent to zero. We can't do much about that, but as a DV is more expensive than an upvote there should be limits to the damage.
Front ends may need to block stuff if it breaks local laws where they host the site. Images are off-chain and those who host them can delete if they deem it necessary.
It seems Twitter is blocking some content that may be considered political opinion, so Musk must be in favour of that. They will get take-down notices all the time for various stuff.
BTW On St--m my account appears to have no posts or comments as they blocked it for my criticism of the company.