You miss the point here. Zappa was writing this in an era where non sense in lyrics was not frequent at all like nowadays and he wrote it as "humor"
You know what they say--beauty is in the eye (or ear) of the beholder (or listener). But putting nonsense in a song and giving it a title doesn't make it anything but nonsense, no matter what year it was composed, and my point is that I wouldn't use it as an example of why yesterday's lyrics are better than those of today.
But this, of course, is only my opinion. Unlike Rick Beato, I will not state that Don't Eat The Yellow Snow is pathetically bad when compared to music of today.