How could it be that according to the Torah of Rav Abadi one is permitted to eat cheese pizza from a non-kosher pizza place?

what about considerations of the oven being not kosher? Reicha? Zeiah? The pizza pan on which the pizza rests being not kosher? Gevinas akum?

a reply would be much appreciated.

in general are we just allowed to make kosher food in not kosher ovens? I am not understanding this.

best regards,