I'd absolutely be hurt, barring some reason for the uneven split. (And I definitely acknowledge there are plenty of valid reasons, and need might be one of them, even if some of the reason for that need was self-created by bad decisions.)
It's my parents' money, and while they are of course entitled to do with it what they want, I'm entitled to have feelings about those choices. If they gave it all to a charity, I'd not bat an eye. But to prioritize one relationship over another in some way? Of course I'm going to be hurt.
If parents gave on child a new car for Christmas, and the other got a pair of socks, I don't think the response would be, "It's their money to spend as they see fit. Just pretend it didn't happen." I guess I consider inheritance like a gift. It's certainly not obligatory, but once you decide to participate in gift-giving, it's sort of cruel to pick an obvious favorite. Maybe some of that "gift" mentality comes from the way my parents have always talked about their will.
I don't think I'd disown them or stop visiting or anything, but I'd be really wounded. And since my parents have talked to us about their estate and will, I'd likely ask them for their reasoning, because, as I've said, we've had pretty open conversations about it. Hopefully I'd find some clarity and peace from that conversation.
I think part of the disparity in responses here is that people are applying the question to their own family dynamic. My family dynamic is one of respect, openness, love, and respect. And beyond that, my sister and I are both capable, financially secure, respectful, and involved with my parents and their lives. So something like this would be shocking and painful and difficult to understand. In a different family, I can see why it wouldn't be out of context for something like this to happen.