Could IM Be The Next Step For Google?
Monopolies may not be bad if they are regulated. Unregulated monopolies, on the other hand, are bad. They are bad because of bad behavior. They may start off nice, but without competition or regulation, they will turn towards bad behavior.
I don't know what you mean by, "it's called capitalism." There are lots of things called "capitalism" and in many of those cases, we try to encourage competition and discourage the formation of monopolies. Antitrust is a very important part of a market economy.