Having been at business school, I'm not sure I would read too much into this. I think you would be surprised at just how terrible some people are at managing their time, which spills over to managing their e-mail. The other thing is that for really popular schools, you have to realize the amount of e-mail that they are getting and some people are just utterly ridiculous in their questions.
My personal opinion - I think it's absolutely inexcusable that someone connected with admissions or a club liaison/president would not respond to your questions as they can delegate this off. Clearly given your results, that's not the norm. If they're not going to respond, they shouldn't put their e-mail address on there.
That is a lot of e-mails to send, however. To be honest, if I happened to find out that you sent e-mails to a big slew of people, I likely would not answer your e-mail. If you're sending 20 e-mails, you're e-mailing 5% of their FY population. If everybody does the same, imagine how swamped people are.
Finally, I would agree that Ross students totally killed it when I e-mailed requests. They were soooo helpful.
_________________
"Egotism is the anesthetic that dulls the pain of stupidity." - Frank Leahy