If you look at the studio audience for this program, you can see exactly where the TV target audience was aimed at.
Therefore it stands to reason, that Flea was going to be voted in as the best bass guitarist.
How many early 20 somethings are familiar with The Chilis? Lots.
Same question about the other bassists, not as many.
Simple maths.
If the show had been done in a more schoastic manner and was screened on say, BBC4, then God know what kind of atrocity would have occurred.
"And the award for The Greatest Bassist Of All Time, voted by you, BBC4 viewers goes to...."
Anyone?