There are some people who think that the church cannot change its teachings; therefore, they think that it has not changed its teaching. People who think that the church can't change its teachings divide, generally, into two camps.  One group (represented prominently by Archbishop Lefevbre and his followers) reject the teaching of Vatican II about religious liberty because they think that it represents a break from the older teaching.  The other group accepts the teaching of Vatican II about religious liberty but they think that it is reconcilable with the older teaching. In my experience, there is not much to be gained from arguing with people in either camp. I would enjoy seeing them argue with each other.