In can tell you right now anyone reading this site is in a completely different universe of tech competency than the general public, and even professionals who aren’t tech-focused.
You would have lost many of them simply with then jumble of letters “UTF-8”.
Gen Z has skills in what is available and popular today, just like the previous generation had.
With CSV exports, there's already a good bit of training you have to do WRT the column layout, file format, headers (or not), cell value formats, etc. There's far more lift involved in training users there than ensuring they select "UTF-8" when they select CSV.
And, there's really nothing technical about it, as they don't need to understand what "UTF-8" actually means any more than they need to understand what "CSV" stand for. It's a simple ask in a list of asks.
I weigh this against having every developer now believe they have to check/convert every character set, which can be unreliable and produce garbage, BTW. And, speaking of garbage, there are some encodings that you won't be able to convert in any case, so it would be technically impossible to preserve data integrity without pushing some requirement on the source up to the user.
So, it's about tradeoffs. And, again, if asking users to choose UTF-8 is the difference between customers choosing your app or a competitor's, then you probably need to be more worried about that than your charset encoding.
Of course, if that charset uses code points not available in your app's native charset, then you're kind of back to square one (unless your use case tolerates garbled or missing data).