Google is a company large enough that you can always find fringes that contradict their main philosophies a business model within the same company. They do not contribute proportionally to their revenue nearly as much as the other FAANG companies.

Yes, they do some OSS work; some of it is even good quality; most of it is not, and is open sourced only to increase market grab (looking at you, Android). They are just a mess. We can all cherry pick counter examples, because of how messy they are.