Man, even if I somewhat understand Java as a choice, because it's basically the lowest common denominator for lots of devs, it is also that. It's not very fun to code in Java.
I've only looked into Spring Boot shortly, but that also looked like the antithesis of fun to me. Tons of boilerplate, heavy-handed processes, a million best practices and documentation to read before you know how to correctly use it.
I mean, if they want to do this, then more power to them. But fun is still important for projects that people do in their freetime...