If something like this isn’t possible and you don’t actually need consensus to push through changes then the whole “distributed” part is just a fiction and we’re really talking about a centrally controlled network. Miners are just basically threatening to vote against the EIP if it comes to it.
Threatening to vote against a bill if it reaches the floor in its current form isn’t an attack or violence. It’s just a message that if you want it to pass you should probably change it.
You don't need a miner majority to do fork the chain, both versions (with and without fork) will exist and whichever is most valued by users/the market tends to "win" and bring miners back in because they like money.
Unlike your voting on a bill analogy, the reality of blockchains is that both universes can co-exist.
A better comparison would be that a billionaire decided to take over just because he had more cash.
Why should this threat of violence be treated differently than the act itself? Miners are threatening to do the one thing their entire existence is supposed to prevent. They're cutting off their noses to spite their faces, instead of enjoying another year or so of profitability