I think the best story I have about SW is something my wife told me....
Back in the late 1970s, the wife was teaching Junior High.
Whenever her class got too out-of-control, she would threaten to bring SW albums to class and play them all day.
It worked...they would scream and then STFU.
Slim Whitman was unfairly maligned and ridiculed, IMO. Sure to "contemporary" audiences of the mid-late 70's, his unusual yodelling and falsetto style was amusing, but that doesn't change the fact that Slim Whitman was an immense vocal talent who had a mega-hit in the 50's with "Rose Marie".
Here is a later live performance of "Rose Marie". I don't know about anyone else, but I think it's gorgeous:
Ditto. You have to place yourself in the time period to fully appreciate the talent. Having World War 2 parents and partially growing up in the 50's, it was more about the music than what was cool. Slim "owned" the genre.