Pretty sure that's purely an academic argument and irrelevant in the real world since the disk brakes that are pretty much a universal feature of thru-axle equipped bikes require much heavier forks and rear stays than rim brakes since the braking forces are concentrated at the wheel hubs, not the rims. That requirement pretty much eclipses any fork lightening advantage that might come from the marginally higher rigidity of the thru axle/fork connection.

BTW, why is this posted in the 50+ section? I don't see how it has anything to do with older cyclists. Probably should go in the road or mechanics section.