

I think what is happening is that Ukraine believes that signing the deal will result in a range of outcomes from neutral to positive, depending how and when the US renegs on their side of it. But without the deal the outcomes range from neutral to very negative, so making the deal is the clear right move even if you believe it won’t do anything.
Why would an optional feature be a deal breaker?
It also seems like an issue that could be easily solved by whitelisting.