As far as a quick google search got me, it seems pretty open with the only caveat being you can't sell or monetize it... how is that not open source?
open source doesn't mean source code is there. open source has a specific definition. There is a list of acceptable open source licenses, as defined by OSI. similarly there is a list of acceptable free software licenses, as defined by FSF. Broadly, the two lists are the same. Commons Clause is definitely not open source.
https://commonsclause.com/#faq
> Is this “Open Source”?
> No.