because they can't find enough locally to meet demand.
From the article:
https://www.washingtonpost.com/health/2021/06/19/dog-rabies-azerbaijan/
The Centers for Disease Control and Prevention has launched a multistate public health investigation after at least 12 people were exposed to a dog, imported from Azerbaijan by a rescue group, that tested positive for a rabies variant.
And some of them are purchased at puppy mill auctions in the US, despite the rescues always telling people not to buy from puppy mills. IOW, dogs from puppy mills get laundered through rescues.
https://www.washingtonpost.com/graphics/2018/investigations/dog-auction-rescue-groups-donations/
An effort that animal rescuers began more than a decade ago to buy dogs for $5 or $10 apiece from commercial breeders has become a nationwide shadow market that today sees some rescuers, fueled by Internet fundraising, paying breeders $5,000 or more for a single dog.
The result is a river of rescue donations flowing from avowed dog saviors to the breeders, two groups that have long disparaged each other. The rescuers call many breeders heartless operators of inhumane puppy mills and work to ban the sale of their dogs in brick-and-mortar pet stores. The breeders call retail rescuers hypocritical dilettantes who hide behind nonprofit status while doing business as unregulated, online pet stores.
But for years, they have come together at dog auctions where no cameras are allowed, with rescuers enriching breeders and some breeders saying more puppies are being bred for sale to the rescuers.