For me the easiest tell is the up front, unprompted, and unsolicited declaration of nonpoliticalness. When someone takes the time and expends the breath to announce how nonpolitical they are, what follows is almost always a rant about how everything/everyone else is too political these days, and that of course leads into something between status quo advocacy and outright reactionary/regressive sentiments for some fabled time before those wicked politics were visible to the nonpolitical ranter. 
People that are hostile to service workers. Some just want to take some ideological stand against tipping when the service worker doesn't really have a choice and needs those tips to survive in the current unjust system in a way where ideological purity gestures toward that service worker just look like being a greedy and sanctimonious asshole. The worst of such people will actually declare, shamelessly, that they believe that service workers don't deserve a living wage. The implications of that are 
worthy.
I may get shit for this, but I'll say it anyway: this hair and beard combo, seen on living people. 
I have yet to meet anyone in person with that look that wasn't a chud.
(If one of you is a comrade with that look, I am sorry in advance for the prejudice and if I ever meet you in person I will atone by buying you a drink or something.)
I see, thanks for explaining!
If you're interested, I'd like to talk more some other time (I'm ungodly busy and tired all the time right now) on the "being anti-GMOs is anti-intellectualism/science" bit, because as I've said before, food scholarship, and food activism are my chosen field of struggle, and I think there are good conversations to be had there.
I think many parts of movements for/about food have had the misfortune of getting started by privileged white people, and putting their concerns over basic humanity. But there are plenty of food-related movements like La Via Campesina who oppose GMOs on a political and ideological level, so we shouldn't be throwing out the baby with the bathwater.
i would love to learn more some other time! and i understand that there are real reasons for opposing gmos especially for indigenous people. I think the original Luddites were based as well. I still think anyone who says the words "I dont eat GMOs" instead of "i dont support gmos" is privileged as hell. like even if youre farming all your own food thats still very privileged, and theres really no other way (other then deluding yourself or paying an insane amount of money) to live "gmo free". i still think most people are anti intellectual poc included, and this is for good reason gestures to history but its our job to empower people with factually accurate information, (im thinking long term here). I would even agree the gmos currently are puting more harm into the world than good but anyone who claims they are inherently unsafe is just factually wrong. and the potential for gmos under socialism could do more than just end world hunger, we could end full illness and diseases, we could eliminate the need for pesticides one day, very importantly we could counter the effects of climate change (that genie is not going back in that bottle). lets chat later!
it'd be cool if your future conversation was public because i'm interested too