This particular quote, in context with what went before it, refers to people who have previously occupied the offices of the president and the pope in general, not these two specific people. In any event, the conflict is not one-directional as you imply, since Leo is specifically responding to Trump's words and his actions in Iran. It's true that Trump is breathing fire at Leo who is deftly using verbal jiu-jitsu to respond, so in that sense the hostility attribute is definitely one-sided. But since Leo is engaging instead of ignoring, he does have a role, however softly pedaled, in the conflict. You may disagree, but that's how it looks to me.