Not true at all. It'll only show some of the comments others will be hidden until you click on them, making the screen jump around the screen as gp said.

old.reddit.com alleviates this but not for much longer I'm sure.

Then the lovely firefox will periodically decide not to allow 'trusted site exceptions' disallowing you from visiting old.reddit.com. All in all I find it's too much work most of the time.