I would have been weirded out by this specific ad, because when I worked at eBay one thing that got highlighted in a companywide announcement was that some executive had decided to stop running ads for eBay against google searches for "ebay", because that is obviously pointless. (And that this saved a ton of money on advertising without impacting traffic at all.)
With a result like that, I wouldn't have expected them to go back to advertising ebay.com on searches for "ebay".
That's probably why the malware author targeted the eBay keyword. Without any real competition, it would be cheaper for them to win top of page placement.
I would have been weirded out by this specific ad, because when I worked at eBay one thing that got highlighted in a companywide announcement was that some executive had decided to stop running ads for eBay against google searches for "ebay", because that is obviously pointless. (And that this saved a ton of money on advertising without impacting traffic at all.)
With a result like that, I wouldn't have expected them to go back to advertising ebay.com on searches for "ebay".