Walters spoke just before Bell, 17, was freed on $45,000 bail after spending 10 months in jail for beating a white classmate.
"He goes home because a lot of people left their home and stood up for him," said the Rev. Al Sharpton, referring to the Sept.20 march. "We do not condone violence of any kind. ... Upon this young man's shoulders is a movement for fairness."
His parents at his side, Bell, who did not speak, walked out of the LaSalle Parish courthouse, flanked also by Martin Luther King 3rd and Sharpton, who recently supplanted less media-savvy local activists to become Bell's spokesman.
An all-white jury convicted Bell after his court-appointed lawyer failed to question any witnesses. The conviction was thrown out this month when an appeals court said he should not have been tried as an adult.
Walters, who is being accused of treating black offenders more harshly than white ones, said he decided not to appeal the ruling.
He said he would retry the case in juvenile court as soon as possible.
"I believe that it is in the best interest of the victim and his family not to delay this matter any further," he said.
Walters charged Bell and five black friends - known as the Jena 6 - with attempted murder last year for punching and stomping white classmate Justin Barker after a series of ugly racial incidents in town.
Walters later reduced the charge to aggravated battery, which could still put the teens in prison for 20 years.