The logic is that this isn't a sign of google being a monopoly and that it has more implications than just being there to avoid anti-trust actions.
People can use all sorts of language, colloquially, and it can be interpreted in many ways.
You could absolutely use language within the company like 'crush the competition' wherein the culture is fully product oriented, great quality, support etc. and 'win the market'. That's perfectly legal and frankly ethical.
Legal's job is to protect from scrutiny and litigation, in which case, they will, among other things, say 'don't use this language'. Because it could be used as a kind of evidence, even if it's totally contextualized and misunderstood.
They will also obviously advise the CEO and product leadership on materially illegal activities, but it's unlikely that rank and file are going to hear about that.
For example, colluding with your industry partners on hiring practices ... you're not going to be privy to that.
If the company is not getting sued, legal is doing it's job. The rest of the equation mostly up to the rest of the executive team.
This works less well when employees are not taught from birth only the language Google's legal team want them to learn.