eBay removes feedback for many reasons: some good, some not so good. But eBay never explains why feedback was removed or reinstates it once it is removed.
Without knowing all the details of a transaction, the contents of all messages sent and received, what the feedback comment said exactly and the outcome of any eBay case, it is impossible to say with any precision why a particular comment was removed.
Comments can be removed for violating policy, but very few buyers think their comments actually violated policy.
https://www.ebay.com/help/policies/feedback-policies/feedback-policies?id=4208
Sellers can get feedback removed if the seller can demonstrate that the buyer attempted to use a threat of negative feedback to obtain something the buyer was not entitled to.
In some cases where the feedback relates to something outside the seller's control, such as a shipment delayed by a declared weather emergency, eBay may remove the feedback.
There are other instances where feedback can be removed, such as if the account was hijacked and used to sell scam listings. There is no point saddling the innocent victim of a hijacked account with bad feedback for someone else's scam.
Top-rated sellers that offer unconditional returns can get some feedback removed if the buyer is refunded.
The fact that some sellers can get some feedback removed does not mean that all sellers can get any feedback removed; there are plenty of sellers that have bad feedback ratings that are unable to get those removed.
For all its flaws, and the feedback system is far from perfect, taken as a whole the feedback system is still a useful tool to determine if a seller is delivering on what the seller is promising. Rather than relying on just a number or a percentage, there is no substitute for actually reading individual comments seeing how far back a seller's history of sales in various categories extends.
