He is far from alone in thinking that. Even among music critics that are generally positive about U2 there has always been a fair amount of criticism of his voice.

Ironic nickname, then ("Bono Vox" being the original form)

TIL what that actually means (the wiki bit below). Its also the name of a hearing aid company in Ireland [0], making it even more ironic. Pretty sure this is where the name originated from.

Found out that (according to wikipedia)[1]:

"is an alteration of bonavox, a Latin word which translates to "good voice"."

[0] - https://www.bonavox.ie/ [1] - https://en.wikipedia.org/wiki/Bono