It's true that advertisers care about public opinion. In some circumstances, with some products, a limited kind of public opinion may be all they care about.

For example, if I have a lemonade truck, the sole purpose of which is to generate pocket change for myself, and I find out that the west side of the city roots for Little League West and the east side of the city roots for Little League East, I adjust my local ads accordingly for Game Day. I do not authentically care about either lemonade or Little League. I'm just selling something for the sake of selling it. So I'm going to run lemonade ads that play off people's willingness to pay me an extra dollar for guessing their preferred sports team.

But in other cases, ad agencies care about something else. A billionaire is paying them to make an ad campaign, and they have to satisfy their client's ego, sometimes despite what market research tells them will sell the product to the widest number of people.

Or, there's a nuance to how they understand "public opinion." As a hypothetical example: Market research may reveal the public as LGBTQ-accepting and interested in LGBTQ-inclusive companies. However, because of new anti-DEI and anti-queer laws, corporations may feel the need to project a "straighter" public image so the feds don't shut them down. A straight-washed marketing campaign by a company that intends to comply with anti-LGBTQ laws could be intended to reset public expectations about the LGBTQ inclusion they're no longer going to deliver. The ad doesn't necessarily give the public what it wants according to people's authentic desires. Rather, given the clay of public opinion, the ad attempts to mold it or wield it to serve an external agenda.