Didn't realize our entrance into the 21st century meant that a bunch of 12 year old addressing me in my classroom as "Joe" is suddenly acceptable.
Not so sudden. It's been phasing out for a while now.
I'm not old-fashioned, nor conservative, but it's just not on. (for me)
You might not be conservative but it's pretty conservative for people to insist on it, I think. Maybe it's because I'm only 25 and maybe there are a host of reasons why we have this difference of opinion but it would feel weird for me to have this conversation:
Student: Flasyb! Help please.
Flasyb: What did you call me? It's Mr flasyb to you!
Student: Sorry Mr flasyb.
They can call me by name, position, Mr, whatever. All that matters to me is how they say it.