You didn't really answer the dependency argument though.
Until the data for a static website becomes large enough to make JSON parsing a bottleneck, where is the problem?
I know, it's not generally suitable to store data for quick access of arbitrary pieces without parsing the whole file.
But if you use it at build time anyway (that's how I read the argument), it's pretty likely that you never will reach this bottleneck that makes you require any DBMS. Your site is static, you don't need to serve any database requests.
There is also huge overhead in powering static websites by a full-blown DBMS, in the worst case serving predictable requests without caching.
So many websites are powered by MySQL while essentially being static... and there are often unnecessarily complicated layers of caching to allow that.
But I'm not arguing against these layers per se (the end result is the same), it's just that, if your ecosystem is already built on JSON as data storage, it might be completely unneeded to pull in another dependency.
Not the same as restricting syntax within one programming language.