What's bad or irrational about being manipulated by marketers and advertisers? I don't see how buying something because some marketing convinced you of its worth is irrational.
Listen to your sentence, once you factor out the internal contradictions (emphasis mine):
> What's bad or irrational about being manipulated by marketers and advertisers? I don't see how buying something because some marketing manipulated you into thinking it was worth buying is irrational.
> I don't see how buying something because some marketing convinced you of its worth is irrational.
It's not as much that they convinced me to buy something, it's that they did it by using data they got by essentially spying on me.