I just installed Red Hat 5.2 a couple of days ago ( true story ). It is so light-weight with its Fvwm window manager, bash 1.2, and GCC 2.7.2. It even had Netscape Navigator! Who could ask for more? Anything more is bloat!
Just kidding. Bloat is installing things you do not use or that do not make your system better. I think some desktop environments add bloat. Mostly though, even the heavy ones represent a smaller fraction of system resources than their ancestors did on older systems.
If you have 3000 packages you use, who cares? However, if you have 3000 packages and only use a dozen of them, maybe your system is bloated.
I use a lot of older hardware. So, I like a fairly lean base system. I still use a lot of software though. I don’t think that is bloat.