I didn't know about this, so I looked it up: it's because they sell prescription-only abortion medication and ship directly to consumers, where it's legally only available via prescription and medical oversight. Fundamentally they're blocked for ignoring medical regulations. There were some appeals, but the argument is that access to abortion medication is already a well-protected right, so that this is dangerous and unnecessary, and it's not possible to block that while unblocking the rest of their educational resources.