To be fair, ads on a map aren't the same as Windows 11 start menu ads – the former are useful and contextual.
I feel the story being told would be more equivalent to what Microsoft is doing rather than Google.
That said, advertising is like a virus, and every company and product is eventually infected by it. It's too tempting to not monetize your customer's eyeballs once you have enough of them.
I actually consider the windows start menu ads less objectionable. At least you can turn them off (for now). There is no way to disable ads embedded in the maps app. And it’s only useful and contextual if you’re using the map to look for somewhere to spend money. I rarely do this. I’m using it to check traffic, get directions to somewhere, or exploring out of geographical curiosity. In all of these use cases, ads are an unwanted distraction.