ETH being a scam is more likely BNB trying to scam us. If you look at it If ETH is a scam (just a speculation) The market will tumbling down because ETH is one of the largest coin out there. If it turns out being a scam how do you think people would think about cryptocurrencies generally. They will have doubts which can result on the downfall of crypto. But no, ETH is not a scam if it is then it should be long gone when it reached it's ATH back in 2018.
I agree with you. Sometimes such opinions of beginners do not even want to pay attention. Many, without having studied the project, unfortunately make hasty conclusions.