Not true at all. Everyone can participate. If more participated they could easily overturn the whole system.
yes everyone *can*. but you have people who's full time "job" is to meddle while the people whose lives they meddle in are busy living (working, raising families, hobbies).
Yes, but they were elected to that job. On a whole it is a good system. There are elements that are not perfect. There are different places with different approaches.
Depends on if this is a popular vote election, of a majority of districts election. There are pros and cons the each system. Germany uses both for their elections I hear.