I have been seeing this extraordinary hate for nft, i find it really irritating, i can understand some criticism but the way they make it look like it is a sin. I mean first of all art is subjective, the points they use to criticize can be easily applied to modern art. For me most of modern art is crap but it has value because people believe in its value simple as that. Even currency is just a paper but it has value because people believe in its value. This is somewhat same hate bitcoin gets even to this day. And i know the same people who are criticizing NFT will be first in line to get NFT once it become more common and once they see profit.
Maybe there is some criticism towards NFTs because of that, however you are correct when you say that things have value simply because people believe they do, this is the subjective theory of value and it is the current accepted paradigm when it come to determine the value of something, so you are not wrong there, however the main problem people have with NFTs is that you do not really own the piece of art that is being sold and there is no legal protection either saying that you do, so in a way people are just buying glorified images they can get for free on the Internet, making NFTs useless as an investment.