Much of the case rested on how tightly the browser was woven into Windows —that MS was preventing competition in the browser space (via the strong arming tactics) but the “bad thing” they did was the tight browser integration.
> the “bad thing” they did was the tight browser integration.
It's true, but it was only "bad" in the eyes of the law because of their monopoly. If Microsoft hadn't had a monopoly then their strong arm tactics would have been fine. No one would care if I went to Dell and said "you can only sell computers with my OS on them if you also include my browser."
In the US you can be anti-competitive if you don't have a monopoly and you can have a monopoly as long as you don't engage in anti-competitive behavior. It's only when you have a monopoly AND engage in anti-competitive behavior that you get in trouble.
That was only an issue because it was used as a deliberate tactic to prevent Netscape Navigator from competing with Internet Explorer. Which was challenged because of Microsoft's monopoly position.
Tight browser integration was not illegal in and of itself.
