Being opinionated is a core feature of a boilerplate.
The problem is how it's labelled as a true generic solution instead of being a JS SaaS boilerplate. Developers often either have specialisations or preferences, and luckily we have more than one option for each kind of application.
See SaasPegasus for a good example. Clearly Django oriented. I have my own boilerplate for my work in Laravel, but I don't brand it as the new saas kid on the block.
No gripes against OP, looks like a neat setup. Just the messaging reads to me off. Like it's focusing on the OSS side of it in a weird way. Plenty of boilerplates exist out there that aren't paid solutions, and all stack their own preferred dev tools that are majority open source. It's as if this were a product called "peanut flavoured peanut butter".