Greenwald had previously worked on the Anthrax story of 2001, where a couple of high profile people got sent a sophisticated Anthrax variant in the mail.
It was supposed to be foreign terrorism at first, later it was found that the strain came from a U.S. research facility.
Biological weapons aren't allowed by treaty. Research how to combat biological weapons however is allowed. So many countries produce strains in biological research facilities under the guise of defense.
That is precisely Greenwald's point, he has never claimed that bioweapons are manufactured in Ukraine. He has claimed that dangerous biological agents might be present, like they were in the U.S. in 2001.
It takes a lot of history and reading to understand Greenwald. The man is a walking encyclopedia, very careful in his statements and touches issues of great complexity. One can rarely refute him in a one liner.
