It's pointless arguing with people like him. That type will enjoy a minyan with fresh food in Timbuktu and then spit on their way out. I've seen it with my own 2 eyes.
pretty funny that you refer to "people like him," without knowing a thing about "people like him" other than that he thinks your ideology is problematic and that your rebbe wasnt the nasi hador. unlike some people around here, i don't believe in bashing behind peoples backs, and if i wanted to spit, i would do it on the way in.
i would daven b'yichidus in timbuktu. and i wouldn't eat the food of mishichists, not anywhere. now you know a bit more about "people like him"
I fail to see how being even from the extreme mishichist camp would affect your kashrus. Deluded, yes. But it ain't kfira al pi halacha.
because if someone has a din of a tipish/shoteh, then they would not be reliable as far as kashrus is concerned. at least not in my book (or those of many others careful about what they eat).