Sorry for the late post, but does the Church not teach that if you do not hold all of the required dogma you are excommunicate yourself de facto?
Even if you do not agree with something, or are struggling with something such as sex outside of marriage, that is different than accepting the teaching and working towards fulfilling it with Gods grace then just outright dissenting from it.
Let us be honest, the only reason to dissent from something like sex outside of marriage and contraception is not going to be based on any theological reasons but pure selfishness.
Dissenting from things like papal infallibility and holy orders is probably more of an educational issue, even contraception. But certainly not sex outside of marriage, that is obvious enough.
It is a lack of teaching of the consequences of these actions, a lack of discipline and authority on the part of people teaching the faith because many times they do not want to hurt peoples feelings, not to mention at least in the American culture it is soaked with protestant feel good once saved always saved faith that is seeping into the Catholic mindset.
for instance, I met a woman the other day who was much older than me, just about to get her degree in Theology, and did not even know that purgatory was a doctrine that had to be held. Me, someone who is not even fully confirmed in the Church, had to show her in the Catechism where her position was against Church teachings. She probably changed her viewpoint on this since, but it just goes to show the type of education and trouble our faith is in right now. Pray to God to elect a Pope that will make the Church stronger again, and pray for the people that are being misled by the society we live in.