Deal breakers are things that are limits. Limits are–in general–a good thing. It’s not that you’re saying that women–or people in general–are fungible, but you’re saying that people that fit any of these criteria won’t work.
IIRC, Dan Savage has said that there’s no settling down without settling. You can–should–have limits, but if it’s more than five things, you need to look at yourself very, very closely. You aren’t going to like every single thing about your partner, but you have to be able to accept them.
I could say, for instance, that I prefer people that are heavily tattooed, pierced, scarred, branded, and implanted. (…Which limits me to about .0001% of the US population.) But that’s not a deal breaker; I’m not going to reject someone because they don’t fit that particular preference, even though my body modification is important to me. On the other hand, I absolutely will not date anyone that doesn’t have a worldview that’s grounded in reality, e.g., is religious/“spiritual”, or believes in any conspiratorial nonsense, because I couldn’t have respect for a person like that. THAT’S a deal breaker. I won’t date someone that wants children; I’m unfit to be a parent, and I had myself sterilized a number of years ago. Again: that’s a deal breaker, because as with religious garbage, it’s a question of basic values.
But when people ask for your preferences they want to know your actual preferences (the positives), not the dealbreakers.
For example, if I asked someone out to lunch and asked what kind of food do they prefer (their preference) then I don’t want to hear a list off all the foods they dislike.
Continuing with the food analogy.
The problem is that I’m basically up for trying almost anything.
I know what I foods I probably wouldn’t like (paprika for example).
And there are certain foods that I like more than others, but there is no hard preference.
Asian food? No problem.
Pizza? Love it.
McDonald’s bit plain but always reliable.
Kebab? Nice.
There simply is no preference, as long as I like the taste and it fills the stomach, I am happy.
But the point of saying that certain things are dealbreakers is that, outside of those, anything is within the realm of possibility.
Do I prefer people with “extreme” body modifications? Sure. Is that a requirement? No.
With food, maybe I prefer Brazilian steakhouses, but the only thing I really dislike is pasta, sandwiches, and deep-fried everything. I’m not going to exclude Thai, Indian, Ethiopian, or Polish food, just because it’s not my favorite kind of restaurant. I’m literally going to be fine with anything that isn’t on my dislike list.