A couple thoughts:

When you see someone waiting for/getting a grope, you can't assume that they are an 'opt-out'. They may be an 'involuntary medical opt-out', ie, someone like John McCain, who can't 'assume and hold' the position in the scanner. Not all TSOs route you to the WTMD instead; some will challenge you, implying that your limitation is not real.

When I explain my limitation and the TSO counters with the usual 'long wait for groper, invasive grope, machines are perfectly safe' (none of which make my body magically capable of assuming and holding the position), I now (respectfully, obseqiously) ask them: if the machines are so safe, why has TSA refused to allow AFGE (TSA union) to conduct independent testing on the machines, and why has TSA refused to allow AFGE to fund and provide dosimeters for TSOs? (TSA said only TSA can issue dosimeters, and it will not fund them).

Since this is the truth, I hope the TSOs go back and verify it for themselves.