I see nothing in what you post that defines non-Catholics taking communion in a Catholic Church as a mortal sin and see nothing in scripture that does so either. I have not yet checked Catholic websites to see whether this stand is part of Catholic tradition. This may be more difficult because if I can't find anything, it may mean that I'm not looking in the right place. It seems that approaching a Catholic priest may not work if some have strayed.
So far then, I find nothing that I have done regarding taking communion in a Catholic Church as a sin to be forgiven; this may change if I find something and there is something to find.
A friend who invited me to a Latin Mass doesn't expect me to be a passive onlooker like a member of an audience in a theatrical performance - the expectation is that I would participate. That is the reason that he would be embarrassed and the reason that I'm in a pickle.
Should we ask for forgiveness on an issue for which we find nothing to say that we have committed a sin? A kind of security provision?
But now it’s not a naïve mistake is it, as you know. Adam and Eve is a different situation.In the case of Adam and Eve, they were punished for making a naive mistake - hindsight thousands of years later doesn't alter the fact that they made a naive mistake. If I read you correctly, I could be punished for making a naive mistake - at least Adam and Eve were given some warning; I was not.
And even today I see no warning that as a non-Catholic I should not respond positively to my friend's invitation. And I see no reason that says I committed a sin 30 years ago by taking communion in a Catholic Church. By the way, as is the case now, 30 years ago I was invited to participate - I regarded the invite as a privilege and not a right; this still holds true.
And quite right, I don't want to hurt the feelings of my friend.
