This is one of those weird categories to me, because... to me... that depends on a lot of factors. At the end, asking "What Level" is almost moot, and can be considered offensive, because it doesn't really mean anything depending on the group running it.
If it is a genuine question of interest, then it's a launching point for some great stories as to how they got there. If not, it can imply that 'gatekeeper' mentality, because if you haven't gotten to X point, you really don't understand the game... (at the same time, they should probably ask what you mean as well, for just that reason- getting instantly offended leads to less bridges than it builds, for sure...)
I've had D&D games that ended or *capped* at level 5, or 10, and that was some world-altering drek to the ones that played it. At the same time, I can make a level 20 character in pretty much any system with the rules in front of me and join a game off the bat for the fun of it.
Even Michael Chandra's question of "how much karma are you at" in SRM isn't telling, really if you ask me. So far, I've played SRM's pretty much exclusively at GenCon (which means I was playing with 20-30 karma under my belt by the end of the last season in Chicago, when other players were sitting pretty with over 100 or more) and my character's Knowledge Skills meant more than my combat skills at the end, because my character was native and I personally knew the lore (again, during the last few seasons with Chicago) so I knew what a native Chicago squatter would know about, and the questions to ask.
I won't lie, I was... less than optimal in a lot of the fights (being a relatively newbie combat mage vs. a background count of -4 in some cases can really hurt!) so I leaned a lot less on my character's stats, and what I actually *knew* about the world (which was reflected in my Knowledge Skills) to help my teammates succeed by making rolls that allowed me to tell them life-saving information... and when you're about to face off with what could be a group of friendly ghouls in what would be a misunderstanding, or in the bowls of an insect hive with a vampiric insect shaman trying to do terrible things with an immortal creature... all I have to say is knowledge is power, my friend...
I've also been playing D&D since it was called "Chainmail" and my current GenCon Pathfinder "Societies" character is a level 2 Dwarven "Treasure Hunter" (Rogue, but he'd never admit that) that my dice have rolled horribly for the past two years at GenCon, but had fun with nonetheless (and rarely hampered the team with those rolls, while they've enjoyed me playing him, so I guess there's that...)
This isn't bragging about what *I* personally knew, but how I applied it. Which is a roundabout way of saying 'It's not about power, but how you play it'. Me? I'm more interested in what do you play, how do you play it, what's the most fun to you?
Plus, it's how it is perceived versus how it's intended. Gaming (tabletop and video) has evolved over the years, and the definitions have grown (and that's not a bad thing in the long run- it only increases the survival of it, and the ideas that drive it)
So if you are inclined, instead of opening with 'what level are you?' roll with "what's your favorite part?" or "Tell me about your character!" You'll likely get the same information you wanted in that question, but also a view of what part of the game is important to them.

Also note, if you haven't intended it, you've never been rude or elitist to anyone. If they read that into your question, that's at least partially on them.
Just my 2 nuyen.
Crunch~