The reason is because there is some kinda thing in RB (think its called TAURIN) or something that is dangerous for ppl with weak hearts.. thats why it is banned.. and because of too high coffein level..
taurine. reports have not found that taurine is dangerous to humans in the amount found in energy drinks. likewise, it would take an extremely large amount of red bull to reach a dangerous level of caffeine
vodka and redbull can be dangerous. stimulant + depressant = not good, but again, it would take a shitload of vodka and redbull to affect you.
i'm sure that the countries in question are just waiting to see how things play out (until "more is known"). a little bit of similar discretion has saved a shitload of people in a lot of countries. thalidomide is something that immediately comes to mind