> I wasn't raised Catholic, but the way I heard it, committing a venal sin counting on it being negligible because it was venal is, itself, a mortal sin -- which tickled me at the time.

No, a sin is either venal or mortal. The intent of the sinner doesn't enter into it.

> Also, that only the sins since your last confession, or communion, or something, count in any way at all.

If you confess a sin and ask forgiveness, it's forgiven. Your slate is wiped clean.

> Or what, exactly, would be meant by a "virginal purity test".

Simply that many in social media demand a level of purity in thought and action from commenters and other writers that rivals in its puritanical zeal the worst excesses of the most ignorant village mullah.

> No. You are tying yourself in knots; which is your privilege. Please don't entangle me in them.

But if virtue signalling is sanctimony, a point which you have not refuted, and complaining about virtue signalling is sanctimony, then complaining about sanctimony is indeed sanctimonious. Any entanglement is of your own making.