But anyway even if your OS ships with perl/python/ruby installed by default (and also the right version) it probably doesn't ship with whatever Postgres library they're using so you'll still have to deal with extra dependencies anyway. And talking about Windows, installing node tools on Windows with npm is on the whole much easier than doing the same with Python/Perl/Ruby, so there is that.
If you want to make an argument that it should have been written in some language that easily compiles down to a single binary you can just download and run, then perhaps people would agree with you. But I cannot see how Node is in any way worse, harder or less common than Perl/Python/Ruby.
OSX comes with Ruby and has for ages, although I think that's being phased out.
But I cannot see how Node is in any way worse, harder or less common than Perl/Python/Ruby.