I disagree. To me, the literal meaning of "fuck" is "to have sex." I see the qualifier literaly as meaning "the next phrase is being used in its original sense, not its figurative sense."

I see it similar to using \ in regular expressions. In the regular expression "\.", the \ acts much as the word literally, and modifies the special character so that I get the literal/actual meaning as opposed to the figurative/special meaning.

As for your example, I think it's meaningless. The phrase "fuck up" is a figure of speech, and has no literal meaning. It just has a meaning.