“Pope’s have done much worse. Yet no false doctrine was taught.”
Are you claiming that the Roman Catholic church does not teach that the path to salvation is open to Muslims, and that the Pope was wrong to kiss a Koran, therefore?
All salvation is through the Catholic Church, which Christ founded. Non-Catholics, and non-Christians, have the possibility of salvation if they cooperate with the grace that God has given them. There is also the concept of invincible ignorance. The possibility of salvation exists if someone is not a Catholic because they never really learned what it was through no fault of their own(e.g. lived in a jungle, or even a Christian who doesn’t fully understand Catholicism).
I think kissing the Koran was a bad idea. Again, popes have done worse and may very well do worse in the future.