
Because the learning curve of Javascript has the lowest barrier of all languages, so contributions will naturally be overly abundant The accessibility of Javascript is uncanny. You can use any web browser to write Javascript using the browser's dev tools, I know of no other language that accessible.
The odd thing about Javascript is that as it evolves it becomes easier to use and more standardized but, strangely people find it more and more difficult to write themselves. And again there, I know of no other language that exhibits this uptake of delusional behavior.
While you might not be in it, Javascript has by far the largest estranged clique of developers that blindly run into walls that are self constructed.