Looks like Hamilton, Ontario (YHM) is class D to 4500 out to 7 NM from airport center. The ILS approach plate to 12 is below. Rockton airport is a glider port, as can be seen by my snapshot. Looks like, based on approach plate distances that both the SEFBY IF and APGOM waypoint are in class E airspace. The 767 could see the glider and gliders (with rare exceptions) only fly VFR, so it seems possible for both aircraft to be legally where they were. Since a glider has the right of way over powered aircraft it was appropriate for the 767 to give way. And since most gliders have no electrical systems then per Canadian regs they aren't required to have transponders or ADS-B.