[ultima ratio]

You are mistaken about the infallibility of ecumenical councils. They are infallible only when they declare doctrine dogmatically. Vatican II specifically stated nothing it said should be considered de fide, i.e., as infallible. It declared no new doctrine, but repeated much that had been previously taught. The fact that it insisted that Latin should be retained for the Mass as well as Gregorian chant, should clue you in that what it said was was pastoral only--and therefore merely advisory.
As it is, much of what they have advised, much of it liberal pipe-dreaming, has turned sour the past forty years.

[sitetest]

Dear ultima ratio,

So you, too, are saying that an Ecumenical Council can teach what is not true?

sitetest

[Catholicguy]

. They are infallible only when they declare doctrine dogmatically

Another error. ALL Ecumenical Councils are infallible by their nature