The first response rather contradicts itself, it says that the Pope is infallible when Canonizing Saints and then after that, "Not Infallible" which then leads to the disclaim that His Holiness "cannot make a mistake". This practically renders Papal Infallibility as illogical as a Pope cannot be "Infallible" and then "Fallible" at the same time or when "Canonizing Saints". This is simply akin to me saying that I'm "happy" and then at the same time, "not happy". It simply doesn't make sense.
Admittedly, I used to believe and even defended this Doctrine in a discussion about Roman Catholicism with some Protestant lecturers in college before.