It's funny because it's true.

It would be funny, if it were true ! Many of those 'rules' are dubious. Maybe its late and I just dont get it?

They are funny because each of the rules contradicts what is required by the rule itself... i.e.

"Proofread carefully to see if you any words out." left out the word leave.

Yep, that's why I found them so funny, they are direct contradictions! I about fell off my chair reading them.