The act of making a parameter private was changed at some point (2020 maybe?). Instead of placing the parameters under the Private Parameters section, it was changed to be an option under the Manage User Parameters. For workspaces that were built before the change was implemented and then opened in a newer version, the Private Parameters will simply be a parameter group and will have no bearing on the parameters actually being public or private. You can get rid of the Private Parameters group by dragging the parameters out of it, and then simple delete. Or you can rename it to something more meaningful.