The fact that it meant something else to someone else is, if you look closely, the entire point of the anecdote.

And the phrasing, "Apparently, ...", presents this as if it was hard to foresee. It was definitely not hard to foresee.

What is easy to forsee in a conference room is not as easy to forsee in a crowded street with tear gas and shouting and rubber bullets flying.

But, again, Ken White seems to be having trouble seeing it in retrospect. Is that not weird? The tweet is phrased to suggest that the Marines are using unusual terminology. They aren't.

"Apparently..." would have been the perfect way to describe my reaction. I didn't realize that "cover me" meant "lay down suppressing fire" to Marines. I guess it makes sense, but that's not the meaning I would have expected. So I would probably have been just as confused as the cops in the story. I wouldn't be surprised if most cops would have been similarly confused.

So yeah in conclusion, I don't really understand the point you're trying to make.

You'll find Popehat is a heavily sarcastic poster.

Read it in the sense of "I told my toddler they can't have ice cream three times a day and apparently that makes me a meanie".

And yet it apparently was hard to foresee for at least one crucial person...

That’s why the post says “cover me”, not “cover fire”.

Well, "cover fire" is a noun, and can't be used as a command.

It's called that because it's how you cover people.

If you ask someone to darn your sock, and they do, will you complain "hey, I didn't say 'darning needle'"?

A marine saying “cover fire” is asking you to shoot.

A cop saying “cover me” is asking for something the marine might call overwatch.