I definitely could not apply this stereotype to real life. It sounds more like a "this-stereotype-sounds-fun-so-I'll-laught-and-say-it's-right" thing than anything real to me
I would say that IRL, the line between STJs and NTJs is often pretty vague and lots of STJs end up mistyped as NTJs only because they're clever and show tertiary Fi. Personally it took me the longest time to get the hang of the NTJ-STJ difference, so I suppose a lot of people on this board might have the same problem and not even know. Therefore (based on the archetypal use of INTJs in fiction, for example) they might type every cynical, sharp, rational person with hidden kindness as an INTJ, while they're in fact ISTJs, and they might not recognize the Ni in their nice "boy-next-door" friend and label him as an ISTJ. I know I've done both.
Personally, female INTJs are one of my favourite types of people. My mum and one of my closest friends are INTJs - they're not the kind of person who everyone likes, but after you get close to them you discover a hidden treasure. Not only they have loads of healthy common sense (so needed for this INFP) paired with great sense of humor and insight, but they're also really good-hearted and sensitive (although they're good at hiding it ). I don't have much experience with male INTJs but they sure make an effort at understanding me, which is very appreciated. ISTJs make good girl-friends as well; our friendships are very steady and light-hearted, but as opposed to INTJs I feel I have a slightly "mentor" role there (while INTJs maybe feel they play a mentor role with me). As for STJs males, I've been attracted to them romantically but the relationship gets very demanding after a while.
On the whole, I'll be stereotypical and say that being "mean" or being "nice" really doesn't apply to cognitive functions. Also, what one sees as mean another might enjoy, and what one sees as nice another might not appreciate.