I'm aware I might be fighting a losing battle here but the term is "expansionary" not "inflationary".

Inflationary means that the value of a currency tends to go down over time. Expansionary means that the supply of a currency tends to go up over time.

Bitcoin is mildly expansionary at the moment because the rate of coin creation is (presumably) greater than the rate of coin destruction. At some point this will flip and it will become contractionary.

Regardless, Bitcoin is obviously highly deflationary as the value of a Bitcoin tends to go up over time.