I don't think it has anything to do with the prevalence of wls, because this reaction was prevalent before wls was common.
I think it's more as Shyttowngal describes it, wanting to know not WHAT you did, but HOW you found the strength, commitment, and support to do it.
I've talked with a lot of people about weight loss in the past and currently too, and I think most people do realize what it takes to lose weight (at least broadly) it's just the amount of failure they've experienced makes the process seem unfathomable.
It's like when my husband is cooking, and I ask him what he's making, and he says "breakfast," or "food." No Sh... Sherlock! Could you be a little more specific?
It's not a dumb question, it's just one that requires more than the simplest answer.
The only thing I ever mind from people is if they start making excuses that minimize what I've done: "I just don't have the time to exercise like that", which I feel implies that I don't have as many valuable things going on like that, or when they say "I wish I had your self-control", which I think implies that there's something different about me that I can "just not eat", when really it's been a ton of work to figure out how not to overeat.
I know that's not how people mean these things, and I reply politely, but they do kinda bug me.
Yeah, what I don't like about the question "How did you do it?" is that it generally marks a shift in the conversation, away from me. It's really no longer about me at that point. It's about to become about them. What they seem to be asking is, "Tell me what you did so that I can try it."
Which is why so often their answer brings it all back to THEM, when ostensibly, we're talking about me.
There is nothing more naked than their responses at that moment. This is when people apologize, get defensive, bristle, say something plaintive, or make a joke that usually consists of them demeaning themselves. Or when they reveal that they actually dislike me.
Quite honestly I am glad there is no magic pill or quick fix to losing weight the easy way. That would mean that I am stupid for wanting to lose weight permanetly the hard way.
The only people I have known in real life who kept the weight off (whether they had the assistance of surgery or not) have all worked at it... hard. Changing their eating habits, making time to exercise, dealing with the emotional issues, etc.
I actually had a friend TELL me a week or so ago that...and I quote..."Science is against me on this one. There is no way I can lose the amount of weight I want to lose without surgical intervention."