As an American living overseas, this is one of my pet peeves. I am cut off from a large part of the eBay sales, because of this increasingly common "no international shipping" policy, which is almost entirely an American phenomenon: sellers in other countries almost never say/do this. It makes Americans look very bad.
The vast majority of overseas buyers (and sellers) are legitimate, not scammers from Nigeria. Insist that payment from overseas buyers clears fully before shipment is made, sure, because recovering items sent overseas is more of a hassle and costlier, but don't ban international shipments altogether. Although technically every seller has the right to set their terms ("I only sell to redheads of Irish descent who buy me lunch on Tuesday afternoons at 2:00on cloudy days" is probably a legitimate term of sale), to adopt a blanket ban on international sales is, IMO,
morally even worse than saying "no sales to blacks" or "no sales to jews" or "no sales to Poles", etc... because it excludes a larger number of people, who don't even have anything in common except they aren't located in the U.S.
The increasing number of American eBay sellers who asopt this policy tend to come across as arrogant, lazy, ignorant, incompetent, bigoted, narrow-minded, parochial, and/or out of touch with the global economy of the 21st century. International shipment is not difficult these days at all. People in countries with far less advanced shipping/transport networks than the US manage to do it, and the buyers pay for the higher shipping cost anyway, so what is the problem? Americans overwhelmingly had ancestors (and probably still have distant relatives) who used to live overseas, too... were (are) THEY automatically scammers or otherwise unworthy because they weren't in the US? Well over 90 percent of the planet's population lives outside the US. The "no international sales" crowd frustrates me and makes me almost ashamed to call myself an American!
Rant over.

Just wanted to express a viewpoint that seldom gets expressed, but that I'm sure is felt by at least tens of thousands (and probably several million) of would-be overseas ebay buyers with cash payments ready --including thousands of Americans like myself, who just don't happen to be living in the US.