The part where that service doesn't exist and isn't close to existing.
Distance from mailbox to live virus is a few days of bench work from a semi-competent biochemist.
And yes, this service claims to have safeguards. Does every service? Does every future analogous service? Are those safeguards guaranteed to be robust against totally novel pathogens?
Answers: No, no, and no.
Still, even though your estimates are silly, they aren't silly enough to change the conclusion that this isn't a comforting security barrier, so I suppose we agree on that much.