I think Java had a bad reputation on desktop for a long time. Every application I remember using back in the day was extremely sluggish, felt like a skinwalker with regards to UI, and hogged memory.
FWIW; I use the Jetbrains suite every day and I don't have a problem with it at all. Compared to, say, VS Code, I think it is pretty snappy stuff.
I do love their IDEs though would point to them as being the exception not the rule.
Wasn't that bittorrent client early mid-2000s with the blue frog logo written in Java? I think I remember the author back then saying something like, "it's just a project I started to try out [some new java gui library]". I don't seem to remember speed issues using it.