Quotes from Richard Lederer and John Shore

A semicomma, we should note, doesn't exist; we just made the word up. But it sounds like a punctuation mark that should exist, doesn't it?

[S]ometimes... quotation marks are an absolute crime against humanity.

The rules of punctuation seem arbitrary. How can they not, when an apostrophe looks like nothing in this world so much as a comma that can't keep its feet on the ground? Or when, by simply placing next to that wafting comma its twin, one creates (of all things) a quotation mark?