He means that the original statement is so vague that not only it is not true, but we can't even say that it is wrong.

It's like if I said:

"What if zebras are green and red, but we see them as black and white because we don't drink enough water?".

It kind of sounds like an actual logical argument, but it's not even wrong.

I admit it could be worded better, but that doesn't make it "not even wrong", it makes it poorly worded.

It's not the wording -- it's the content. Or rather, the lack of it.