Well, I’m sorry you were offended. I assure you that nobody here actually thinks music ed majors are second-class citizens, because that would be unreasonable and backwards.
I did not make that particular meme, but the impression I got from it was that it was commenting on the fact that music education is sometimes treated like the ugly step-sibling of the music department and takes a backseat in terms of visibility to the performance major.
No one is arguing the point that teaching is a ~noble profession~. Like you said, anyone dedicated and talented enough to become a music major of any kind should know and appreciate the value of teachers.
Sort of. You don’t have do be a fantastic, virtuosic singer, but you will need to be able to sing on-pitch and with a modicum of quality (unless, of course, you’re planning on being a vocal major, in which you’re obviously going to have to be pretty good). Some schools/professors are more strict on this than others. My guess is that if you’re good enough at music to get into university for it, you’ll be able to match pitches just fine.