Technically it is not the monopoly that violates the rights but the loss of a protection that virtually mandates that a right will be violated. This is true in theory and in practice.
I again disagree with your conclusion that monopolies inevitably lead to the violation of rights. I'll even go one step further by saying the government busting up a monopoly is an act of violating the rights of those who own the company. I realize that is likely an unpopular position for me to take (as if that's ever stopped me) but hopefully my explanation will appeal to the rational faculties of those willing to listen.
1. You admit, although you qualify it with the word "technically", that the
existence of a monopoly doesn't violate anyones rights. Then, "technically", government has no cause to bust up the monopoly.
2. You refer to a loss of "protection", so I'm inferring that you consider competition to be a level of protection and you're not actually suggesting that laws cease to apply to monopolies. Is that a correct understanding of your statement?
3. Since laws do not cease to apply to companies simply because they are a monopoly, the rights of individuals (consumers, employees etc.) are still protected by law. If the company does, in any capacity, violate the rights of individuals, the law would apply and the victims would have legal recourse.
4. Its a violation of the owners rights to have their monopoly busted up by government for nothing more than the "crime" of existing. Violating the rights of an individual (or company) based on what he
might do sets a dangerous precedent that threatens the rights of all individuals.
5. Government Sponsored Entities (GSE's) are more dangerous than any private sector monopoly. Enron was committing fraud by cooking the books, Fanny and Freddie were doing the same thing, but it was the private company that was put out of business and had their executives put on trial while Fanny and Freddie execs faced no legal challenges and their companies were bailed out at the taxpayers expense.
If you have the time (50 mins), I invite you to watch the following presentation given by Alex Epstein about monopolies:
The Monopoly Myth: The Case of Standard Oil