Why can't we leave bad feed back on time wasters

[garet.parke]

So I've had a lot of people bidding up items then cancelled within minutes of auction ending but you can't give bad feedback to warn others. I know how to block them after but how do we prevent it as annoying 

[jckl1957]

Even though you understand you can't do it, you have left negative comments for buyers.

This is feedback abuse and could damage your account.

All you have done is added to the buyers' positive feedback score.

[plpmr]

"you can't give bad feedback to warn others"

that's because eBay stopped sellers leaving buyers bad feedback over a decade ago, because sellers were abusing feedback and could not be trusted.

The fact that you leave false positives for buyers proves eBay's decision was correct, as false positives are serious feedback abuse.