The rabbinate’s silence is a form of acceptance. They should have forcefully come out against this ruling. Watch the homos try and force orthodox rabbis to perform such weddings. Then they’ll have to do something.
The Israeli rabbinate is a government institution. The non-government orthodox establishments have a very low opinion and expectation of anything connected to the Israeli government.
As with cases in the USA, the hotel is not considered a religious site and does not advertise itself as such.
You’re right, the Chief Rabbis’ offices and chareidi groups may regret not being vociferous about this.