Members of the establishment have zero freedom to speak their mind. All they can do is repeat the group think nonsense that furthers their collective power and privilege.
So anyone who speaks their mind freely, particularly about sensitive topics, and who goes against this group think is not part of the establishment.
People may call them "controlled opposition" if they have any platform or popularity at all, but if a true message is getting out who is one to quibble over who says it?