"I added bacon to my ice cream because bacon" [is the most awesome thing ever] (and if you don't already know that or don't agree, I don't want to try defending it).
"The project failed because politics" [generally causes everything to fail] (and if I start talking about that I'll start ranting and no one wants that).
"Root beer in a square glass is beer because math" [uses "square" and "root" as opposites] (but if I said that explicitly it would harm the humor of the joke).
Contrast "I added bacon to my ice cream because of bacon", which would suggest that everything you need to know is there and it is the nature of bacon to be added to ice cream.