Java in a large way has been eclipsed by most other languages, and developers kind of have a way of making fun of old technologies, like a lot of the same jokes are made about PHP which is still very popular but outdated. In reality Java is also still incredibly popular and knowing it is certainly a benefit. It’s just a collective joke.
Normally when I see a post I don’t care about I just keep scrolling. I respect that you went out of your way to let random strangers know you’re gonna keep scrolling lol