The GCs, short for gender critics, describing multiple people. I cannot call multiple people a gender critic. It has to be gender critics, plural. I thought this would be obvious especially to someone who is always a stickler for language and how words must be used in their original forms and not updating it for modern usage.
The equivalent for trans people would be using The TW for 'the trans women' when talking about a group of trans women who are all doing the same thing as a group. I.e. the TW who use hormones. Not offensive, not derogatory, not dehumanising.
You are clearly choosing to see something you want to see.