I assume Google's legal department is not irrational and that they are worrying about something that could happen to anyone.

Hum... Rational (from the point of view of the entire enterprise) bureaucracy bodies probably exist, but they are not common. But that second part "something that could happen to anyone" is completely unfounded. It may be because of something that could happen to you, or it may not. There is no reason to assume either way.

As people keep ignoring on the context of software architecture, you are not Google.

You publish open source code so that others can benefit from it, and if Google uses it maybe billions of people will benefit from it, so I disagree.

Everyone has different reason to publish their code using open-source license. I like sharing my code but I don't like when multi-billion dollar company make a profit from it for example. Ofc, that's what I agreed to when I release my code under open-source license, but we are all free to have different sentiment about it.

This is an individual choice; people have motivations beyond "maximize usage of my code".