Do you think it is the pharmaceutical companies, or just state regulators like the Medicines and Healthcare products Regulatory Agency (MHRA) in the UK, and the FDA in the US?
If you are making unsubstantiated claims about cancer cures, these regulatory agencies will come after you. GcMAF may well have anti-cancer effects, but I think these regulatory agencies want to see good studies first.
This 2008 article by Cancer Research UK discusses the small number of GcMAF cancer studies that have taken place, and points out the flaws in them, and concludes that "although this particular approach isn’t all it’s hyped up to be, harnessing the power of immune system could be a very potent way to treat cancer".
This review 2017 paper from Iran, which is more up to date the latest studies, says:
I've never really looked into the claims for GcMAF's efficacy against cancer, so can't really comment much.
But it is a shame that this treatment has become more difficult to find because of the cancer controversy.