Maybe they are willing to sell and are just saying this to drive up the price.

Or maybe they don't want a competitor to have access to their secret algorithm, and threaten them globally. This way they lose only one market.

Another possibility is that they will teach users how to use a VPN, and are confident that enough of their users will do it.

Or maybe they think saying they're willing to shut down will make some of their users lobby against this bill / organise protests / call their representatives. (This probably won't work.)

Companies are ultimately motivated by money. They will do whatever underhanded trick they can think up to get it.