I recently committed to the Solana proposal, which was then closed because of fraud. But I am still committed to a closed question! I cannot uncommit (button's gone). How do I uncommit, and why is this happening? Is it in case the proposal is reopened? But, in that case, why is the Uncommit button gone?
It's not deleted yet, only closed. It'll be auto-deleted 30 days from its close date, at which point it will also disappear from your profile.
Letting everyone go and uncommit because it's now closed would spoil useful information: knowing how far it got. We keep closed proposals around for a bit so people can potentially learn a little bit about what happened before it completely disappears. Having all the numbers start decreasing after-the-fact would not be useful.