Conflating a Ruby on Rails app to all of Ruby is just not really fair. It’s like comparing Lombok to Java. Lombok is a hot fucking mess and Java app with it is gonna have difficulty at later points.

Aside from that (I think rails is honestly terrible), just looking at the repo I can see that RedMine doesn’t use bundler, which is the singular standard in the Ruby community, so it’s like saying “a project I use uses Ant under the hood so Java is bad”. Like I said, there’s a reason that Rust and Elixir based their build tools off of Ruby’s.