These companies are not US-based. AliExpress is a division of Alibaba, a well-known fakemaker's sales website based in mainland China. So they're free to make, sell and export fake
US coins as much as they want, since they're not breaking Chinese law.
It is, of course, illegal (under American law) to import them into America unless they are stamped "COPY". And rest assured, these won't be unless the buyer specifically requests it. But the Secret Service isn't randomly opening everybody's overseas mail, just on the off chance that they might be importing fake coins. They can only act on definite tip-offs.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis