Answer:
Monopolies hinder competition because by definition, they are anti-competitive.
Explanation:
A monopoly is a firm that is the sole provider of a good for which there are no close substitutes.
Monopolies charge higher prices than they would in a competitive enviroment, and for this reason, they benefit the monopoly at the expense of the consumers.
Governments can set several policies to reduce monopoly power. One policy is simply to prohibit monopolies from forming, which is the case for most industries in developed nations.
Another policy is to simply take over the monopoly, and make it a public enterprise, so that the extra economic benefits of the monopoly are shared with the people (at least in theory).
He specifically spoke out against the Jim Crow laws
