They didn't ban it because of the taste! AFAIK, it causes inflammation in the brain.
"Aspartame is one of the most rigorously tested food ingredients ... has been deemed safe for human consumption by over 100 regulatory agencies in their respective countries."
https://en.wikipedia.org/wiki/Aspartame#Safety_and_health_ef...
My wife is one of those consumers. She gets a headache like clockwork after having something with Aspartame in it. So, we didn't need a study in order to know that Aspartame is bad for us.