There are things that aren't as obvious and may seem counterintuitive. Because company A derives 95% of their profits from ads it puts pressure on product design to not endanger that and also branch out in other areas. It would be extremely risky for such a business to have a cavalier attitude to how they manage user's trust and the information that the ads depend on because, like you said, they depend on that ad income. That is why, if you have to give your private information and the choice is between a company that depends on (safeguarding) it (like Google) vs a company that doesn't care (like mom&pop store), I would be very afraid of the latter's management of your private information, the security of their systems, etc.

If you have a choice to not give your private information (or limit what you give) to anyone then that's obviously better.

> I presume this false equivalence is trolling, since only one of the two firms mentioned derives ~90% of its revenue from targeting ads, and the implications should be self-evident.

No, it's not trolling and nothing about what you wrote is self-evident. Especially when you take into account that one company is the world leader in datacenter security practices and the other is struggling with quality service development.