DKIM & Sender Verification Fails to Spam Instead of Refusing Them

Hello,

I have always clients complaining that some people (sending emails from misconfigured servers) can't send them email because my servers refuse the emails saying the server verification failed, DKIM failed or the message format is incorrect.

Why doesn't WHM marks all the emails, where any kind of verifications failed, as SPAM (and deliver them to the destination) instead of refusing them? Can one option like this be added?

Gmail handles this kind of problems like I suggested. Is far way better marking it as spam than just refusing the email completely...

Thank you.