You are signing USATF documents. They require you to be a USATF member to do that. That seems reasonable to me.
Below is from the USATF Safe Sport FAQ.
3. WHO NEEDS TO BE USATF 3-STEP SAFE SPORT COMPLIANT?
The current list of those required by USATF to be background screened and to complete SafeSport training is expansive. We currently require members of the following groups to be USATF 3-Step Safe Sport Compliant: National Office Staff, Board of Directors, registered coaches, certified officials, authorized agents, club officers, National Team staff, National Committee Chairs, Association leadership, Youth Committee members, AAC Committee Members, AAC Event Leaders, all meet volunteers in an official capacity, Youth Camp staff, vendors with access to athletes.
Not sure I see anything in that list that FS, or even Certifiers would be part of. But Certifiers are in a position of power over others. I agree it's hard to make that argument for FS.