The odd thing is that some people don't!
Thinking back to my schooldays, we were blessed with a very dynamic, motivating and inspiring music teacher who ran the 2 school choirs and 2 orchestras. Pretty much all classical music in those days, but we still owe a lot to her in opening our ears, broadening our horizons, etc. Guess we were mainly middle class (whatever that means), and you had to pay for instrumental lessons, and buy your own instrument after a trial period of hiring one.
One interesting observation was that, in the senior orchestra at any rate, there were far more pupils who were doing the science subjects, than from those pursuing languages and "the arts" - maybe a bit of light relief from all that physics and chemistry?
Folk music was for spare time, definitely out of school!

When my kids (now in their 30s) were at school, they also got a lot of music, with visiting peripatetic teachers of, e.g. violin, woodwind, brass, and all these lessons were free, albeit in groups rather than individual. Also had the choirs and orchestras and a jazz band. Music choices straying into musical theatre and pop, but still no folk! Middle class again. Instruments again had to be bought: over £200 each for a clarinet and trumpet, which may have excluded those not able to afford such luxuries.

Politics irrelevant to all I've just said.