It's tied into so many important things. I mean one of the biggest to me is lack of appreciation for the benefits we've been born into. We have such an amazing potential for long healthy lives in comparison to the entirety of human history. Just throwing that away strikes me as so incredibly ungrateful for all the suffering that people have gone through in the past. Hell, that people are still going through in a pretty large number of places. Choosing shitty foods and ill health is spitting in the face of every ancestor who fought and struggled against malnutrition, disease and injury.  Not to mention the whole environmental angle. Which is ironic because with politics so polarized anyone outright stating that they don't give a shit about the environment will be just nullified as a potential partner. But do the same by one's actions? By needing to drive everywhere, overusing food resources, mostly living on food that comes with environmentally damaging packing and  development or distribution methods? And that's almost every single fat person.  And it just goes on and on. Those are two of the biggest points for me, but they're far from the only ones. Their entire lifestyle is toxic and gross. I find fat as a physical trait to be pretty repulsive. But it's what it says about their lifestyles which takes that revulsion into total disgust.