The Church polices its own, but very slowly, with an eye towards the next few thousand years, not next Tuesday...rightly or wrongly, that is what I see. It is hesitant to step on heresy too quickly, without full (very full) investigation (perhaps due to lessons of over-zealousness in the past). Priests are not infallible, though. If they speak against Church Doctrine, they are doing exactly that, speaking against Church Doctrine. They are not changing Church Doctrine. The sacraments they administer are still (absent special circumstances) still valid. Holy Communion does not become invalid because a priest is a sinner, for example. So, they still serve the Church and the parishioners even when in error. Because they are not infallible, there is some responsibility on parishioners.