See, you dont like the word stupid, and I dont like the word strong/weak. It implies that people are not equal in their decision-making, which I strongly oppose. It also has a patronising touch to it, which I also oppose violently.
You may be weak in the face of marketing claims if you're exhausted, tired, distracted, or have insufficient understanding to question them. You fall back on a subconscious availability heuristic - "I'm always hearing about this thing, that has to be some kind of social proof that it's good".
You have the strength to resist misleading marketing if you have sufficient resources, experience, learning, energy and/or spare mental cycles.
I know my decision-making capacity is certainly affected by things like this. Sometimes I have limited capacity and I reasonably prioritise other concerns.
You are being idealistic and not basing your reasoning on science.
All people are not born with equally capable brains.
That’s just a fact.
People are not equal in their decision making.