Point of a PATCH operation if you error on duplicates?

When trying to submit PATCH operation to add 20 publisher blocks (for example), we receive an error response if one publisher is already blocked. That means in order to avoid an error, we need to request the current block list, check it against the new batch of publisher blocks, and only submit unique publishers.

In that case, it does not seem helpful to use PATCH. We might as well just GET the blocks and POST the entire list.

Am I missing something here? Why would Taboola's practice be to error, instead of simply skipping over duplicates?