I will try address this in general…as to the concepts brought up as well as other aspects readers may not have thought of that we all need to keep in mind:
Is this something we should do??
It certainly is not something we should do.
Even if one does not admit that it calls for the “obedience of Faith”…
and sees it as calling instead for the “religious submission of intellect and will” …such includes our *mind *and how we act on this issue (a person can not just “not use it” there is more involved) which would exclude among other things such activity as described.
Also one does not need to “suggest to anyone that they disobey this teaching” to actually sin gravely in what one says contrary to it…and in the scandal by which one even indirectly by ones words etc …leads others into sin…even into dissent or confirms their dissent.
Not only can there be scandal here on the forum …and out there on the web…(for years to come) but there is even the cooperation in others sin which is another grave sin (mortal sin-same thing) one can be thus accountable for:
Catechism:
1868 Sin is a personal act. Moreover, we have a responsibility for the sins committed by others when we cooperate in them:
- by participating directly and voluntarily in them;
- by ordering, advising, praising, or approving them;
- by not disclosing or not hindering them when we have an obligation to do so;
- by protecting evil-doers.
also germane here is this from the Code of Canon Law:
Can. 209 §1. The Christian faithful, even in their own manner of acting, are always obliged to maintain communion with the Church.
(of course one could prob find various other ways people can sin via this forum…other ways contrary to charity…justice…human dignity etc)
So in our actions and thinking…both here and in the “real world” we need to very “circumspect” and avoid sin in its varied forms. We all need to examine ourselves and how we carry out our daily lives. Following Christ with joy
Now as to if one has committed mortal sin if one has done such in the past? We need to examine ourselves honestly before God and see if they had also the knowledge and deliberate consent needed for mortal sin.
One the one hand we can know that we should not do such and such. And on the other hand it can very well happen that we do something completely unknowingly and not realize it til later that it was not good.
Taking of course into account mans ability to fool himself (or so my wife might suggest such to me at times…

)…
So bottom line is all of us need to take care …and to do as our Holy Father Pope Benedict XVI noted here
vatican.va/holy_father/benedict_xvi/messages/communications/documents/hf_ben-xvi_mes_20110124_45th-world-communications-day_en.html
An important read for us in this forum