Guess what: "literally" has been used as an intensifier, literally, since the 1700s.
And even if it hadn't, no language is static, unless it's dead. Words change their meaning all the time, but I guess pedantic jerks have to find something to snark about or they will literally explode.
The problem I have with this is that using "literally" in this way, is meant as hyperbole, an exaggeration. The whole reason it WORKS is because it means what it meant before this change. A person saying a guy is "literally a greyhound" or that a heavy object weighs "literally a ton" do not mean "metaphorically", they mean "literally" and are simply exaggerating to stress a point.
Changing to this new meaning makes the the word "literally" more confusing than it needs to be for no reason and also changes the meaning of what everyone who uses the word
incorrectly is saying. This is a foolish change and makes me think even less of the oxford dictionary than I already did as its editors apparently haven't ever heard of exaggeration or know what it means.