[murphE]

but what makes you think this particular statement comes under the category of "infallible".

The wording. The anathema is a big clue that it is infallible.

[Wonder Warthog]

"The wording. The anathema is a big clue that it is infallible."

Nope. Church councils are only considered infallible on "matters of faith and morals". The language to be used in Church is neither--it's more like "company policy".