For that matter if you want to buy the meat, you have to buy the bun. Even the government doesn't call this illegal. Whether a web browser should come with or without an operating system is for the market to sort out. If Microsoft pursues the wrong strategy, it will be punished. If it's competition we want, we can't depend on government, the inventor of monopoly.
Competition exists in the absence of government intervention.
Mr. Potato Head, Microsoft Explorer, their makers and distributors and consumers, can get along just fine without Reno.