Source? Because it's one thing for a phrase to be used by a niche group, it's another for a phrase to enter the common lexicon. And then another to make it into the OED or Merriam-Webster.
MILF is still very much in use, go look at comments about Checchetto's MJ artwork LOL
And you're welcome to believe MJ's entrance is the worst of the worst. Awesome! So stipulated! We all have opinions.
All I can do, again, is point to all the evidence and remind people that 1965 was almost sixty years ago and audiences of the time had their own semiotics that might not be easily apparent to readers today :shrug. And regardless, that opening line is still referenced almost sixty years later, to the point that Marvel is trying, again, to make Jackpot a thing. But alas, the character of Jackpot is not even fetch (Mean Girls the Musical film is opening next week).