As an instructor in a wide variety of relatively extreme sports, I find the best thing to keep in mind is not making the student feel inadequate or stupid during his learning process. As such, I avoid words like newbie etc as it isn't going to make the student or new guy feel welcome, and because I've seen 'newbies' put so called experts to shame after a very short time. Not everyone is the same when it comes to how quickly they learn and I've personally seen 40 dive (skydive) guys nail a formation while the 1000 dive guys were fighting to get in. Concentration, hand eye coordination, ability to keep thinking when something doesn't go your way...most of this you either have, or you spend a long time trying to acquire...and may or may not ever get. Those who have it when they start are often quickly at a level that others spend years trying to attain. The same can be said for air consumption, staying relaxed and paying attention to your surroundings.
I'm not saying the 'newb' is one of these guys, what I'm saying is in my mind a simple 'I have my dive buddy plans worked out already' followed by the very good advice, might have been a better (or at least a kinder and gentler) approach.
With that said, I can certainly understand not wanting to buddy up with a guy who might suck through a tank in 30 minutes and ruin your dive. I was averaging approximately 60 minutes on the typical 80ft(ish) cozumel multilevel dive but I did see pairs heading up as early as 30 minutes in....and if I was paired with one of those guys I would NOT have been a happy camper...even being the newbie I am. The trip etc is too expensive to leave the water with half a tank of air unused.
So, in my mind your message was spot on and very justified...but you Texans have never been very good at tiptoeing through a topic. I lured the love of my life from Texas to Denver and have often told her she has all the subtlety of a claymore mine.

It must be something in the Texas water....