Greg, look back at your posts and read where you were forced to admit that the offending sentence viz. salvation and false sects is qualified as an indirect denial of an article of faith. Now, supposing I granted this admission, you have just proven my point, since heresy is a direct denial of a defined article of the Catholic faith. An indirect denial is generally a proposition that leads to the denial of an article of faith by a process of inference or deduction, depending on how the sense of the proposition is taken.
As far as natural worship to God, you have conceded the point. Bringing in statement regarding supernaturally meritorious before God is irrelevant, no one, not even the Council claimed it was. The Council was (wrongly) explaining certain noble truths of the Muslim religion and esteemed them under that aspect (again, absolutely wrong objectively speaking, but true subjectively). Just as you would esteem a friend who is not Catholic but possesses certain natural virtues.