Why anyone would pronounce it to rhyme with "bagel" makes no sense to me (same as pronouncing "gif" with a soft "G"); IIRC (and I am no linguist), in english there's a rule about how something is pronounced based on surrounding letters - and I think that double consonant vs singular consonant preceded by a vowel is one of those rules.
I'm sure there are exceptions, after all (it's english...) - but I have a feeling that if you looked at such words you would find the general pattern to fit.
Again - I am willing to admit that I really don't know what I am talking about; I'm not a linguist, I'm not an expert in english. I'm just some guy who last studied english in high school years ago...
There's really no excuse for any English speaker to interpret kaggle as kagle or kagel.