I was looking at an old Unmerged Match, and decided that there was in fact enough information to re-propose the Merge. First I note that [Merge] is not available as an option under Unmerged Matches. So I tried [Compare], always a good way to start a merge. This produces the usual comparison. I then click on the [Merge them] hyperlink. This produces a big yellow header that basically says "A and B are currently set as Unmerged Match to indicate that the two profiles are not ready to be merged yet." There is then a small hyperlink that says "Click here to remove the Unmerged Match." It is your only choice. Fine.
This leads to another yellow header box, and the text below it that says "Click Confirm to complete the removal. This should only be done if there has been a mistake — if X and Y do not even look like they could be the same person. If the two profiles represent the same person, they must be merged."
In fact, I am sure they are the same person and do want to merge them, but the text here implies I should therefore *not* click Confirm now. But yet gives no other option. I am pretty sure the idea is to click Confirm to remove the Unmerged Match with expectation that you will then do a normal Merge. But the instructions on this page are very user-unfriendly and could use an edit.