In the absence of any evidence or even a sensible motive, what is it? There’s no reason to think Google’s stated reason isn’t true, and as an attempt to obstruct China it would be rather pointless to go after something they have almost no deployed usage of which is starting behind things they do use.

It is their guess at what is happening without proof. That is the definition of a theory. It is about two entities secretly working together to do something harmful. That's a conspiracy.

So... I mean... yeah. The comment is a perfect example a conspiracy theory. Both in literal textbook definition and the broader cultural understanding of the term.