It is sad to see this happening because it seems that they really tried a bit to give in to the demands about ethics. As you mention many changes were made that were around the key issues that Democrats claim to have with this. I don't know what their problems are, and I also don't like this kind of vote along the party line politics anywhere. It can't be possible that no politician from one party independently is not satisfied with the bill, that is very improbable when it comes to humans. Politicians should vote on laws based only on the content of the law, and if they are satisfied with it they should vote like that. Did they even somewhere write exactly what they want from it or are they just making general statements like even better ethics? If they are not specific enough it can be hard to deliver what they want.
That's the reason why Bitcoin's price dropped today? It seemed that the week started well, so I was surprised to see the loss of 5% today, although it is nothing catastrophic or out of the ordinary, but it has made us lose support.
As the OP says, perhaps it is nothing more than a dance to finally end up accepting the new regulation, but for the moment its effect is being felt in the cryptocurrency markets, and not only in the odds of the prediction markets.
There was again belief that it was going to pass or that it had high chance of passing so the market was a bit bullish, but these news contradicted that. Also there is fears of another interest rate hike so both of these things happened around the same time. A loss of 5% is very small for Bitcoin.