Jim's house, Jim's rules, I get it. Just when Jim says there is beer in the fridge, and I go in and find the fridge locked, the bathrooms locked unless I do a special dance just the right way, and no running water, he should not get cross when I leave again disappointed. And tell others.
It's either an open platform or it's not. Right to repair is a thing in some places, and all things automotive can be hacked. I happen to live in the US where there is this law called the DMCA that's used to bludgeon people who point out there are security problems (think car fob replay attacks, or decrypt DVDs) or reverse engineer things the manufacturer feels they don't want them to, so there are some other issues with the lack of support.
CAN and LIN bus systems aren't magic; they just need to annoy someone in a digitally free country enough to go in there and work it out.