Hence the "irrationally grossed out" part. It's not a controlled thing, I'm not choosing to feel grossed out, I just do. So you can understand that your reply was akin to telling an arachophobe: "You're probably a city dweller that's never been to the countryside, we have them everywhere there". It comes off as arrogant and know-it-all.
More seriously, first get really in touch with your phyche. It's hard to underestimate how fucked we can be as individuals when we're bathing in our parents issues. Don't be afraid to consult a mental health specialist, if not in your budget (for US reasons) find friends you can confide in without feeling judged (tall order if you don't have them already I know) or just get a good round of introspection/meditation.
A lot of issues I see adults do is because they never learned to live with themselves and therefore never learned to know themselves, so they're slaves to their own ignored/repressed feelings.
A healthy mind in an healthy body is maybe a cliché, but it will take you far and they usually go hand in hand anyway.
I really don't get your argument...how is me living a theorical "artificial" clean life relevant ? (Which you're only assuming btw)
It's like arguing that getting kicked in the balls is fine because "you probably just live in an artificially painless life, with painkillers and modern medicine".
Also what's your obsession with being filthy ?
Do people who like dogs necessarily have to roll in the mud ? Does a moderately clean person who like licks even exist in your eyes ?
But yes, good job you're a big boy you can proudly show off his dirty greasy burly hands, I guess :D