I have interacted with plenty of people with blonde hair, and plenty of girls taller than me, and even after all of that interaction I still don't feel attracted to any of them. Would it be better for me to broaden the types of people I hang out with? Absolutely. But, it's not like if you have a gay man interact with women for a long time he will suddenly become straight. Preferences are very much biology.
Imagine if everyone started ruling out groups of people based on physical characteristics they'd observed in the people they weren't attracted to. I mean, i guess that means I can't date guys, my dad has a dick and I don't find him attractive. Fucked on girls too, I'm not interested in the slightest in my mother. Even if you wanna go less extreme, let's just consider this: - I have never dated/been attracted to anyone younger than me, does that mean from now on (10 years of dating experience) I should just ask someone their birthday and rule them out? - I have never dated/been attracted to anyone in a frat, does that mean I should refuse to date all men in frats? - Never dated a redhead, should I rule all of them out? Freckles? Curly hair? It's a terrible, illogical idea to start drawing sweeping conclusions about what you like and don't like because you have not found yourself liking it before. Having never consciously been inclined towards something does not mean you never will be. It just means it hasn't happened for you yet. Maybe it will or won't, but in the meantime you're being super close-minded. Why would anyone want to limit their options like that, I just don't get it. I certainly would not deliberately pick people one after the other that fit a very specific mold, physical attraction, personality, whatever. I am put off by people who remind me of certain exes. If I was deliberately choosing from an even narrower pool of candidates I think I would just be reminded of my exes all the time. No, I know why things didn't work with my ex; time to try something different. Why would you insist your partners fit a specific checklist that is the same for all of them, that is like playing a broken record and thinking that if you change the turntable the problem with the record will be fixed. No honey you gotta switch up the record.
I'm not ruling it out based on one person though. I have seriously never seen a redheaded person who I find attractive. I would therefore absolutely say that I wouldn't date a redheaded person. You're making my argument out to be if I find one person in that group that I'm not attracted to, I wouldn't be attracted to any of them. I'm saying I have never found ANYONE who has red hair attractive enough to date. I'm not creating a model that someone needs to fit. In fact, if one day I did find someone who was blonde, or red haired, or taller than me who I did find attractive I may date them, but right now I feel like it is completely fair for me to say I wouldn't date someone with red or blonde hair or someone who is taller than I am. Just the same way I would say I wouldn't date a guy. I'm just not attracted to men.