Advertisers want to make sure their customers don't forget to buy their stuff. This is much easier than actually convincing non-customers to do something new.
Don't let advertising companies fool you. Your entire purpose to them is to be just as valuable as the average slaughterhouse cow
That a pretty simplistic view. I never said ads are 100% true and want the best for you. Ads are informational as they inform you of the existence of a product and their basic characteristics. Small, well-targeted ads can be the only way someone that's just starting could have to let people know about the existence of their product. They don't hold a gun at you to force you to buy a product, they don't remove competition between companies, they don't prevent third-party review sites from existing. Buying or not buying them is up to each individual.
Advertising is primarily about making you buy a product from a particular company, whether it's a good product or not, whether it's right for you or not.
If it were about letting people know your products then 'Nide' would have "if you want these for cross-training the best show are 'Reebob' Cross2" on the advert for their training shoes.
Advertising is almost orthogonal to informative disclosure.