whooops, i was afraid that'd happen
yeats in fact got disillusioned with the middle classes because of a lot of things. During his times - and it continues today - psychology was investigating the reality of group/crowd behaviour. Yeats studied it and read all about how a crowd of people - during a protest, or during a rally, or political reading - would easily become violent and barbarous, like our own riots today. It's very complicated, but his distaste for middle class society was based on his dissapointment as he saw his country wracked by a war for independence, followed by a brutal civil war where innocent victims were shot without reason.
On the note of elitism, yes... i'd like to investigate it... i don't immediately think it's a bad thing right now - i mean, i believe in the equality of rights, and i am a humanitarian of sorts, but the question of readership is not easily homogenised.