I suspect you will find most Victorian (or earlier) genealogy full of Latin - in those days it was a sign of an education - the 'grammar' in Grammar schools refers to Latin not English - I guess these days even the ability to spell is an achievement (:-).
But I agree with you, abbreviations are, like jargon, the language of a community with an assumed common knowledge base - most family historians do not of course share this background and thus can flounder badly.