"Universally considered" is a strange choice of phrase here.
Joe Biden was diagnosed with a stuttering disorder when he was a child. He overcame it through various therapies, but it still occasionally pops up in his speech, as it does with almost every former stutterer.
Biden regularly keeps in touch with several kids who have also been diagnosed with a stutter, giving them tips and encouragement.
One of those kids gave a courageous and moving speech on Joe's behalf at the 2020 Democratic convention.