"According to MENSA, if you get 23 of these, you are a "genius"."
Then the MENSA definition of "genius" is pretty stupid!
Knowledge is what that quiz tests. Exposure to phrases common to different areas of vernacular usage of words doesn't make anyone a genius. It does show an ability to absorb knowledge and apply it to a test if the person taking it does well. That's a good trait, but it ain't genius! It doesn't allow for the very real fact that some parts of the test ignore the availability of recognizable phrases dedicated to specific arenas of communication.
...you are pulling our chain, or MENSA is pulling your chain. ...or both. It looks more like a pop-culture recognition quiz than a MENSA test.