Some relevant history, I think:
After the EqA was passed, the EHRC drafted the initial 3 Codes of Practice, giving guidance on applying it (which have some legal weight, as I understand it, though less than the Act itself, so if they conflict, the Act is the ultimate authority): one for employers, one for services, public functions & associations, and one on equal pay.
However the documents they eventually produced in 2011 did NOT just reflect and explain what the Act says, but (esp. the employers' and service providers' Codes) included several simply incorrect/made-up sections claiming e.g. that "transsexual people" should be treated "according to the gender in which they present", allowed to use opposite-sex changing rooms, etc etc. At the time it seems the EHRC was heavily influenced by activists, and it was a Stonewall champion for many years (though not sure exactly when they joined; they also had an ex-Stonewall CEO as Chair for several years, though that was later!). This incorrect guidance was of course very influential on employers and service providers in writing their policies, & was widely quoted by TRAs to "prove" they had a right to use opposite-sex facilities, etc.
By 2022 though, after a number of court cases relating to sex and gender, and the drafting of new EHRC guidance on single-sex provision that ended up conflicting significantly with the CoPs, the EHRC accepted that they were "out of date, confusing, and out of line with the Equality Act and recent case law", as Sex Matters put it, and agreed to review and rewrite them. (The new Employers' one came out a while back, & the new draft Services one just before the FWS verdict, but will now need some more updating).
Presumably, having managed to influence the drafting of the previous Codes to the extent that they ended up not actually reflecting the law at all, the activists are now hoping they can pull off the same trick twice, and generate new guidance that gives them what they want, regardless what the EqA says. So no wonder they're telling everyone to ignore the actual law, & wait for the new guidance!
Luckily though, there is now a lot more scrutiny to ensure the new Codes, & any other new guidance, are 100% in line with the EqA and SC ruling this time. Plus we have the formidable Baroness Faulkner heading the EHRC now. So however much they scream and stamp, they're not likely to get away with that again!