I keep noticing that statement around a lot in response to certain desktop environment layouts. My first time noticing it was with Windows 8, GNOME3 and maybe Unity back in the days.
With Windows 8, I understand the annoyances with not having a start menu button. But the one thing Windows 8 did for me was forcing me to start using keyboard shortcuts and to search for what I'm looking for. And I still put that in practice even with today's desktop environments. But that's not always the case for other users, so I understand that.
So I'm curious about what your opinion when you see or hear someone say that the desktop environment just wasn't designed with mouse in mind?
Is it an inconvenience using a mouse on certain desktops?
Is it because you have to click more than you want to in order to find what you are looking for?
Is it because the spacing is inefficient, like having to move the mouse across the screen to access certain items?