This was not a rejected match. It was an unmerged match. This means a member was not entirely sure it was a valid match, or perhaps there was a conflict preventing merge (such as different parents on the two profiles), or maybe they were new to WikiTree and feeling timid about merging.
In any event, if another member determines that that an unmerged match is ready to merge, that other member can remove the unmerged match and propose the merge (similar to what Kevin has suggested).