It could be either/or in this case. Probably leftover stock considering Matty Collector's pending closure and sales, especially if it's d-lister characters, but KO companies have been making 98% accurate KOs recently, such as Masterpiece Transformers or Star Wars Black Series which are very hard to distinguish from the real versions.
This can lead to some people wanting the KOs because if the KO is the same as the real deal for half the price, then those people will jump on it just to save money and boost their collections. We also have that weird case where the only way to buy many of these figures is secondhand and the market can get pretty bad, so if we see perfect Trap Jaw clones for $15-$20 or less getting cranked out then those are going to become very appealing to some. But then again, if the seller IDs it as a KO that's one thing, but expect a lot of them to be treated as official, and eBay's policies on fraud sales have gotten lax, you're not likely to pay more sending it back to Asia than it's even worth. Ebay stopped the whole "smash it and take a photo" thing, they want it sent back now.