Microsoft was not found to be 'a big evil' monopoly because there is no law in the US or Europe that prevents a company from being a monopoly. What Microsoft was found guilty was putting up barriers which prevented other companies from entering the market. For example, MS charged the OEMs the cost of a Windows license on every PC sold, whether Windows was actually installed on the PC or not. This meant that the OEMs were much less likely to install another operating system, which creates a barrier to the market for Linux and OS/2 and whatever else.
perhaps you forgot the whole "anti-trust law" thing ??
it may not prevent the creation but it sure puts a hurt on a company as soon as they are found in violation of them....