Same reason we bash politicians. They are highly visible targets and carry a lot of responsibility for the workings of the society we live in. Likewise Java and C# have profound impact on the development community for better or worse. Naturally people will have an opinion.

Same reason lots of people bash America but mostly leaves Luxembourg alone. America influence the lives of many people and don’t always make the smartest decisions internationally.

Criticism isn’t all bad. That is how we move forward. For new languages to have a rational to exist they need to demonstrate that they do something better than the big established players. Criticizing an aspect of Java is one way of clarifying the advantage of a new technology.