This is probably just coincidence so don't take me too seriously but here's what I've noticed:
The professors of my biology/chem courses: "Hey buddy, don't be afraid to ask questions we've made sure to try and make things easy to understand. Here are some extra resourses for you if you're having trouble. We've structured the marking so that you have lots of opportunities to catch up if you have a bad week etc. Good luck! So proud of you all! 🥰"
The professors of anything to do with math or tech:
"LISTEN HERE YOU LAZY PEICES OF SHIT. IF YOU DON'T ALREADY KNOW EVERYTHING I'M SUPPOSED TO BE TEACHING IN CLASS THEN FUCK YOU. WE HAVE ONE TEST AND IF YOU FAIL THAT THEN YOU'RE FUCKED AND IT'S YOUR FAULT FOR NOT READING THE EXTRA RESOURSES I HID WITHOUT TELLING ANYONE THEY WERE THERE. WHAT? YOU HAVE A QUESTION? THAT'S A YOU PROBLEM, IDIOT! 
"
idk, i was in engineering for 4 years and had about 30 professors total. maybe 2 of them were like your 2nd type whereas all the rest were adorable and so so helpful and approachable. BUT i did hear similar fucking awful things about all the computer science professors so ¯\_(ツ)_/¯
Yeah, I have a math PhD and I only had a few guys like this during my undergrad (first year physics, second year classical mechanics, and statistical thermodynamics). Of those only the last one felt genuinely unfair. Hell, in the second one the guy talked shit about "getting rid of dead wood", but it was generally an easier course than the applied math courses at that level (none of which tried to intentionally trip you up).