Be careful with your language here. The Syllabus of Errors condemns religious indifferentism and religious liberty. Religious tolerance, on the other hand, which means tolerating those who practice false religions, is actually consistent with Church teaching. For example, Sicut Judaeis Non says we must tolerate the Jews practicing their false religion, and we are not allowed to forcibly convert them into Catholicism. Similarly, we cannot forcibly convert anyone of any false religion. It may seem like I am nitpicking here, and apologies for that, but this is my first article in my 3 article series on religious indifferentism, religious liberty, and religious tolerance, and they are 3 distinct things.