I did a cursory glance for about 15-20 minutes and this is what I noticed.
https://www.canada.ca/en/revenue-age...rectorate.html
This link is for reporting charities. Based in what I see in general, there's nothing that really sticks out as a way to legitimately report them to the CRA. Unfortunately, it seems like they are on side, but just being open about discussing the other side of topics that we don't agree with and perhaps in a manner we don't agree with. I even read their T3010 and on casual glance it seems innocuous to me.
I then read their wiki and took a cursory glance at their website. No major red flags.
From what I understand from what I read, they are basically contrarians who argue on the behalf of certain groups in Canada. Their sole focus is legally challenging situations on humans rights and constitutional freedoms where things might not have been done correctly because people didn't like the topic being discussed. Whether they agree or not is seemingly not important, akin to the way Voltaire was like. But this was just an understanding based on a cursory glance.
Wilson v University of Calgary for instance went to the Court of Queen's Bench where it was ruled the University Board of Governors lacked justification to refuse a hearing for the students appealing their academic misconduct. I thought that group was a bunch of morons with their genocide awareness project stuff, but I think JCCF was right in bringing forth that the University Board of Governors could not refuse a hearing for the appeal of academic misconduct and should have done the process properly.
Apparently JCCF represented a few salons against Jessica Yaniv as well.
Additionally, they seem to enjoy using the method of acting as intervenor in court cases to have their position on the legal questions brought before the court without actually being the official legal counsel for the individuals and organizations.
I don't disagree that the JCCF message and who they represent really bugs me and rubs me the wrong way. But it does seem that they are legitimate in their operations at first glance and their mandate is objectively appropriate and important in ensuring due process in certain legal cases.
I think your only discourse would be to go to the media about it, but in that situation, you're seemingly just playing into their hands. *Shrugs*