Of course you don’t have anything to add. You can’t find anything that actually shows we’re wrong about traditional Catholic teaching on Catholics attending and participating in non-Catholic services. The only exceptions are solemn occasions such as funerals and weddings.
Pre-Vatican II Catholics just didn’t do it. Especially Popes. Period.
And as for the charge of off-topic, ebbtide challenged the accuracy of a comment made by another poster in post #8 about Francis’ preaching of the Gospel of Jesus. Since Francis doesn’t make an effort to convert others to the Gospel of Jesus (remember “proselytism is solemn nonsense”), then it was certainly appropriate for him to do so.
As a result, subsequent posts are very much on topic.