Is there a reason that the editor of a rejected edit cannot see the reason an edit was rejected?
Normally, you can see the rejection reason on the suggested-edit page. An exception is when there is no rejection reason, which happens if the first reviewer decides to improve your edit and marks the suggestion as not helpful. Then the edit is rejected by Community without reason.
The actual reason for the reviewer to mark the suggestion as not helpful is probably one of
which applies, you can sort-of infer by going to the post and comparing the actual edit with your suggestion.
In this case, though, I suspect something else happened, since the actual edit is pretty much identical to your suggestion:
A user with edit privileges started to edit before you submitted your suggestion and submitted it after you, causing your suggestion to be auto-rejected.