Everyone already has the right to a trial; plea bargains do not take that right away.
Punishing someone for exercising a right IS taking that right away. The government here is deliberately increasing the cost of exercising your right to a trial in order to discourage you from doing so. I don't know how that could be more clear.
You might as well say "everyone has the right to free speech if he purchases a $100,000 free speech license for 24 hours". Yes, in some sense it's true that everyone still has that right. But what good is a right you cannot exercise?
You're confusing "fellow citizens" with "accomplices" here.
Until they are proven guilty, they are merely "fellow citizens". If you were a criminal scumbag and you thought you could get off easy by incriminating your upstanding neighbor, why wouldn't you?
There's nothing wrong with getting a robbery suspect to turn on his accomplices
There is something wrong with encouraging neighbors to spy on neighbors.