Jesus never said ignorance was an excuse for not accepting the salvation offered which all men will know.....that is our mission to reach out with the Gospel Message. Further many Ignorant people have indeed come to him by the faith God gives them to believe. We were all “Ignorant”....to begin with. Be it having no knowledge of the things of God, though he clearly says nature speaks volumes of him, or under false teachings that lead people astray or keep them from the truth of His Salvation message.
Further the Pope said nothing about people ‘Thinking about God” as you indicated. It does not help the Popes poor position by excusing him where there is no excuse.
“... for it is not the hearers of the Law who are just before God, but the doers of the Law will be justified. For when Gentiles who do not have the Law do instinctively the things of the Law, these, not having the Law, are a law to themselves, in that they show the work of the Law written in their hearts, their conscience bearing witness and their thoughts alternately accusing or else defending them.”
-Romans 2:14