With respect, this is false. JDL members were certainly charged with crimes. They were not charged with belongimg to the JDL, since that would be a first amendment violation.
There are interesting reports on state.gov describing the difficulties the JDL caused with the Soviet Union, eg.:
https://history.state.gov/historicaldocuments/frus1969-76v13...
Note that at no point do they discuss banning the JDL or charging members with belonging to the JDL.