It's just a general rule not to go into deco solo.
I have always had a buddy with me whenever I have been deco diving so it has never been an issue for me.
And I have never been on a solo dive where I needed to go into deco, either.
That's a load of BS! I've never heard of that "general rule". I know lots of divers that go into deco solo. It's actually a pretty common practice. If you think you need a buddy to deco with, then that's fine. But don't spout off it's a general rule. It may be your general rule, but not everybody's.