As the person who originally asked "why" I feel like I ought to respond, though much of it is covered by other comments. I used to work in more trad advertising, so my question wasn't so much an objection to working in advertising itself, but specifically Google's version of advertising, which I see as gross overreach into people's personal lives. In other comments people have mentioned YouTube subscriptions as being…
If I sound judgy there, note that you are condemning a lot of people. Not me, actually, but I still take issue because the basis of your condemnation doesn't even make sense to me...
I think ads are a decent way to pay for a service and I prefer targeted ads to generic ads, especially since they are more effective (and if the idea is to pay for the service you are using, that is relevant).
So the issue is the data, and so the fact that Google has never sold or lost their user's data - you seem to imply otherwise - is extremely relevant, and is why I'm OK with them storing my data. In this industry that is very rare, and yet you consider Google the worst - I'm having a hard time squaring that.