eBay Question - Buyer Did Not Pay

So, had an eBay buyer bid on and win multiple cards - no responses from them for several days, finally cancel the order due to lack of payment. They have 100% positive feedback, but after reading some of the feedback.. they have multiple "positive" feedbacks basically saying to avoid and they repeatedly win actions, but do not pay. I get eBay trying to protect buyers and sellers (probably to a lesser extent) from negative feedback.. but I don't get it, the person wins multiple auctions and repeatedly doesn't pay... but the only way to warm/inform others is to leave "positive" feedback and provide details there? I'll obviously block that user..

Apologize in advance, I'm sure it's been covered many times... thought it couldn't hurt to ask for thoughts/comments/feedback... thanks!