"Why is anyone aero towing with a tow hook that will back release?"

Some of us don't have much of a choice. For example the two ASW-19's and two ASW-15's at my field all have both a C of G hook AND a forward mounted aerotow hook. The forward hooks have a back release function as well. Short of engineering, building, installing and getting an STC from Transport Canada for a completely redesigned forward hook mechanism there's not much we can do about this.