But if he is a traditionalist then he would be in violation of certain past teachings:
We furthermore forbid any lay person to engage in dispute, either private or public, concerning the Catholic Faith. Whosoever shall act contrary to this decree, let him be bound in the fetters of excommunication. — Pope Alexander IV (1254-1261) in “Sextus Decretalium”, http://oce.catholic.com/index.php?title=Religious_Discussions
Commenting on this, the Catholic Encyclopedia states,
“This law, like all penal laws, must be very narrowly construed. The terms Catholic Faith and dispute have a technical signification. The former term refers to questions purely theological; the latter to disputations more or less formal, and engrossing the attention of the public....
But when there is a question of dogmatic or moral theology, every intelligent layman will concede the propriety of leaving the exposition and defense of it to the clergy.
But the clergy are not free to engage in public disputes on religion without due authorization... http://www.newadvent.org/cathen/05034a.htm
It does not befit a layman to dispute or teach publicly, thus claiming for himself authority to teach, but he should yield to the order appointed by the Lord." Quinisext Ecumenical Council in Trullo, Canon 64,
The Quinisext Council of 692 was not held by the western church as authoritative and binding, but it is regarded by the Orthodox as ecumenical/binding, yet as disciplinary canons they can be abrogated. (http://www.newadvent.org/fathers/3814.htm
Can. 831 §1 Unless there is a just and reasonable cause, no member of Christ's faithful may write in newspapers, pamphlets or periodicals which clearly are accustomed to attack the catholic religion or good morals. Clerics and members of religious institutes may write in them only with the permission of the local Ordinary. - http://www.intratext.com/IXT/ENG0017/_P2P.HTM
“the Church forbids the faithful to communicate with those unbelievers who have forsaken the faith they once received, either by corrupting the faith, as heretics, or by entirely renouncing the faith, as apostates, because the Church pronounces sentence of excommunication on both.” St. Thomas Aquinas, Summa Theologica; http://www.newadvent.org/summa/3010.htm
"One must neither pray nor sing psalms with heretics, and whoever shall communicate with those who are cut off from the communion of the Church, whether clergy or layman: let him be excommunicated". (Council of Carthage [not found]
* “Do not converse with heretics even for the sake of defending the faith, for fear lest their words instil their poison in your mind.” Bl. Isaias Boner of Krakow (Polish, Augustinian priest, theologian, professor of Scripture, d. 1471)
Catholics justify (if they are to) their public dissent and disputations on current (subject to change) canon law, which states,
Can. 229 §1. Lay persons are bound by the obligation and possess the right to acquire knowledge of Christian doctrine appropriate to the capacity and condition of each in order for them to be able to live according to this doctrine, announce it themselves, defend it if necessary, and take their part in exercising the apostolate. But which is too broad and ambiguous. But as Rome interprets herself, what she said in the past only means what she says in the present, thus RCs are not to base their obedience on their judgment of whether present teaching conforms with the past, but like docile sheep, their basic duty is to follow the pastors.
"It follows that the Church is essentially an unequal society, that is, a society comprising two categories of per sons, the Pastors and the flock...the one duty of the multitude is to allow themselves to be led, and, like a docile flock, to follow the Pastors ." - VEHEMENTER NOS, an Encyclical of Pope Pius X promulgated on February 11, 1906.
So what you’re saying is that according to canon law every Catholic here on FR needs to be excommunicated because they debate about Catholicism?