Weaponization of closed source software could take many forms and is just part of the general weaponization of market mechanisms that businesses do.

Right now it doesn't really affect me that Ableton Live is closed-source. But it would affect me if the main method of sharing music on the internet was Ableton Live project files. And if Ableton had cultivated that situation on purpose they would be weaponizing the closedness of their software.

If we're talking about weaponization, then for sake of completeness let's remember that weaponization of open source is a very powerful business strategy that's been frequently used in the past 20 years, whether to market software, acquire free work, or as direct move, to try and destroy a market some competitor works on.

Some business models - like OSS, and free-with-ads - are like dimension-folding weapons from Dark Forest trilogy: once deployed, there is no stopping them, they just permanently drop a degree of freedom from the universe, inside a shell expanding at the speed of light.