…I think I might have found the answer to my question. The core of it, anyway.
“In the part which commands us to honor the name of God, the command [is directed] to the meaning of a word used to express the Omnipotent and Eternal Majesty of the Godhead, Trinity in Unity.” / “Although this Commandment uses the singular number, Thou shalt not take the name of God, this is not to be understood to refer to any one name, but to every name by which God is generally designated For He is called by many names, such as the Lord, the Almighty, the Lord of hosts, the King of kings, the Strong, and by others of similar nature, which we meet in Scripture and which are all entitled to the same and equal veneration.” -
Catechism of the Council of Trent
And it’s remarkable how much the current Catechism retains of this, albeit in a more condensed form. The really interesting part, though, is the breakdown/explanation of what “taking the Lord’s name in vain” actually means, i.e.
swearing falsely… it’s remarkable how little focus is actually directed to the irreverent use of holy names. Aside from the initial positive command “to honor the name of God”, there’s only one single sentence on the entire page which applies to the question at hand:
“Scripture when it prohibits perjury, says: Thou shalt not profane the name of thy God, thereby forbidding all irreverence towards all other things to which, in accordance with this Commandment, reverence is due.”
So I guess the question can now become (what it should have been all along): Do the phrases “Good Lord” and “oh my God” exhibit a
lack of reverence, or not? It seems to me that’s what the heart of the argument boils down to: some seem to think that such use is irreverent, and
others seem to think that it really isn’t, at least for the most part.
In any case, I think this much is clear: truly irreverent uses of God’s name
are prohibited by the second commandment, but this is
not the same thing as “taking the Lord’s name in vain”. There’s a very real distinction between the two offenses, despite the fact that our ordinary use of the english language tends to blur them together.