Then there are some reasons specific to Java itself. For one, the JVM is just incredibly slow to start up, and I hate having to deal with Java-based tooling. Gradle is infuriating to work with for that reason (and others). I'm also incredibly uneasy regarding anything made by Oracle, I definitely don't want to add a critical dependency on an Oracle product just to be able to use a build system which may or may not arguably be slightly better in some areas. I know OpenJDK is a community project, but it's one that's completely dependent on Oracle. With Oracle's recent-ish hostile moves regarding LTS builds of OpenJDK, I'm even more wary than normal.
[1] You may point out that Meson is written in Python, which means using Meson adds a dependency on Python. And yeah, I think that's totally fair, and I would respect someone's decision to use CMake instead of Meson to avoid adding all of Python as a dependency. But Python falls in a different category for me personally, because: 1) a lot of my projects end up with a build-time dependency on Python regardless of build systems, since Python is what I use for things like custom preprocessors and random scripts; 2) the sorts of systems I care about (Linux, macOS) tend to come with Python anyway; and 3) I trust the Python foundation way more than I trust Oracle.