Actually, I'm not sure you get it. It's not about being big, it's about using a monopoly position in one field to gain entry to another.
If you're big but not a monopolist, and you do the exact same thing, then way less of a problem. Hence Apple could bundle Safari with iOS but Microsoft couldn't bundle IE with Windows XP in the exact same way.
I avoided the word "monopoly" for a reason. The internet isn't a finite natural resource, Google doesn't own it, there are other players in the field, and nothing stops new players fron entering.
You're also interpreting the word "big" perhaps too literally. In your example, Apple is not big in the sense I mean. Microsoft might be, but that doesn't mean I agree with the judgement against them.
If people like your product so much that 95% of the market uses it, I don't see the abuse.
> it's about using a monopoly position in one field to gain entry to another.
It's not about Google dominating the search market. It's about Google leveraging their dominant position on the search market to promote their comparison shopping service, which is a different product for different market.
Think of the competition laws as nerfing your ability to leverage domination of one market into immediate domination of other markets. Companies don't have natural rights, there are only the arbitrary rules of the market game, that are intended to promote general prosperity in the society.
If you're big but not a monopolist, and you do the exact same thing, then way less of a problem. Hence Apple could bundle Safari with iOS but Microsoft couldn't bundle IE with Windows XP in the exact same way.