also one should always be skeptical about the extent they believe they are not influenced by ads. that runs pretty deep. you say you instinctively don't trust it. but when the time comes to buy something, you won't automatically steer yourself towards a product that you have never heard before just because you have not seen an ad for it. having some names in your mind, even them showing up when you do research creates influence.
Such a belief purports that the effect of all advertising is measurable. It clearly is not. For example, someone sees your ad and decides your company is reprehensible. They were not a customer and they decide to never interact with your company. It's not possible to measure this. Anyone claiming it is holds what amounts to a religious belief.
The "generates negative returns" is the next myth in this. Whether or not advertising generates positive returns is not relevant. You can't measure the return of advertising in the first place. Even if you could measure it, you should be comparing it to the opportunity cost of not doing something more productive with that money. Which you also can't measure. No one rationally proposes that someone spends a hundred dollars on advertising to generate $100.10 in revenue is somehow a good use of money.
I can't immediately come up with a scenario in which all of the following is true:
1) The ad-viewer is repulsed by the ad
2) The ad is repulsive for reasons unrelated to your product/company's actual characteristics (otherwise they weren't a potential customer anyway)
3) This accounts for a significant portion of ad viewership (otherwise it's not relevant)
4) There is no social/media backlash (that would make the issue visible)
5) There is a significant positive ROI anyway (that's the only motive to continue that advertising campaign, which is required to sustain both negative and positive effects of the ad)
Take a person that hates being advertised at, a persona that is growing. This person meets all of your criteria. Multiply this person across the internet.
When this person sees an ad, regardless of company or content, they are repulsed because they hate ads. This person likely runs an adblocker so when an ad gets through, they are even more angry. If this person sees this product in the store, they will avoid it.
Take a common example of Coca-Cola. Their ads are everywhere. This person would instead buy the store brand cola even though it has not been advertised at them.