I can't remember if I've posted in this thread before (and don't feel like searching through all ten pages of posts before posting this), but I'd like to say they don't.
Of course, as a kid, grade three and up, I feel like most people outside of my family and close friends (and I didn't have many close friends outside of scouts whom I regularly hung out with or had over at my house) didn't really know much about my Muppet fandom. A few of the near-teenaged people in my life might have sometimes given me a hard way to go about it, but otherwise most of my close friends and family either also liked Muppets or at least tolerated Muppets enough (though I clearly liked Muppets a lot more than they all did).
But I do recall a few times during my sixth grade year, there'd be some adults at my school or church who would ask me what I liked to watch, and I feel they gave a somewhat weirded out reaction to me saying I liked Muppets or Sesame Street, maybe they were just surprised that somebody my age liked those (though I don't think they gave the same kind of reaction to other "kids stuff" that I mentioned).
And I remember in tenth grade, shortly after I had really took in that Muppets and Sesame Street are made to be enjoyed by adults instead of kids (as well as a lot of children's properties), I did mention liking Sesame Street to some of my classmates and they seemed to think it was weird, though we didn't talk much about it afterwards (of course, maybe high school students don't really think about if something "for kids" can be enjoyed by adults, either - or maybe when they do start watching again, maybe with their kids, they pick up on things that make them wish they'd continued watching). But there was one twelfth grade class I took, pretty much all the other students at my table liked Sesame Street as well as many other Children's properties that I'd grown up with, and it was cool.
Of course now I don't think we'd have to worry now. We are in an era when a lot of people value nostalgia. A lot of adults, recent high school graduates, and probably high school/middle school students tend to still like what they did as children, whether less people are outgrowing things or they're becoming more nostalgic (there's a lot of shows I liked as a kid that I stopped caring much about for a long time only as an adult to really start caring about again). I don't think many people (particularly those who grew up at the same time as me or earlier) ever "outgrew" the classic animated Disney movies (I want to say the same about Looney Tunes, at least during the years when the shorts were heavily on television).