Even still, this is an emphasis on looks. If someone suddenly becomes attractive to you because they did something new with their hair, got a makeover, completely changed their fashion sense, or lost a bunch of weight, you have become interested in them because of these cosmetic changes. Knowing them and having some kind of connection prior to this has absolutely no influence on whether or not you find that individual attractive. You think they don't look very good, you would never consider them as a person you'd like to have sex with, then they do something new with their looks that completely changes your opinion on that. Still based on looks, is it not?
Most people either like someone enough to be okay with/actively desire sex with another person, based solely on how that other person looks. This is a super simple binary choice that millions of people can make across the world. If this weren't the case then Tinder would literally not exist. Yes, I do agree with you that people in general would compromise a little bit, but that's not an active choice. Someone is either attractive to you, or they aren't. Most people have a "perfect" look they desire, but of course real life doesn't work that way. If the dude you're flirting with looks good enough to you, it doesn't matter how much of that checklist isn't met by him. You would still be interested, because you're just attracted to him.
Could you potentially become attracted to someone as you get to know them? Of course! Do most people do this? No, I really don't think they do. For many, that initial attraction is what pushes them to try to date that person. If that initial attraction isn't there, why bother asking them out? Why bother dating them? Why spend your time on a gamble like "well maybe I can become physically attracted to them?" You wouldn't. And I don't think most people would do this, either.