Usually just one for keying is removed. However, the odd pins are ground, so maybe it works fine.

Define "did not work". Can't read disks? Or POST error "Floppy drive fail (40)"?

Is that a bent pin? Bottom right on the top one.

I've never seen a drive with (nearly) all the pins removed on the bottom row, but I do have one where every other bottom pin is gone. I would think removing the whole lot would negate the point of using ground pins between data pins, so that's kind of lame. But, there's probably enough resilience in such an old and slow protocol that it wouldn't cause any actual harm.

The ground pins would be terminated on one side which would provide some protection from interference.

Oh... well yeah, I guess you're right. Good point. 😀