Seedha-Saadha or Seedhi-Saadhi generally means kids who were plain studious, didn't/hardly dated, no sex, no drugs, little or no alcohol.
The uncles and aunties of JNU are extremely good at profiling. Give them credit where it is due. Bhenchod gate se pehchan lete hain. Then they do match fixing of the new boy/girl with someone of their batch or a senior. It is only downhill from there on. While the kids do well academically, they are FUBAR by the time they graduate.
My classmate joined JNU. Typical UC Hindu, naive, studious and decent at sports but with plenty of chul in gaand. Joins JNU, gets sucked into the Leftist camp, starts doing drugs, alcohol, making out in the open after dark. Course gets over. Comes back home, joins a topnotch IT company in Bangalore, all is well for the first few months, then gets introduced to a new 'female' interest who is ex-JNU but doing jholagiri as most of these jholachaaps are non STEM and their daflis, utopian world view and art-craft have little or no value in the real world so she snares the chutiya, he starts skipping work for weeks, joins the bimbo in visiting tribal villages, teaches Marxism and Physics to kids who don't know what to make of the two.
Chap finally gets benched and eventually fired. Woman dumps him as who needs a out of job techie with fast dwindling savings. Chap boards a train and goes home. Breaks down in front of his parents, they knock some sense into him, he eventually hooks up with another girl, parents approve, the two get married and leave the country for higher studies. He is one of the top guys in AI-ML for a major giant now.
There are scores of other stories. JNU uncles and aunties are darned good at profiling and generally survivalist and street smart. Many of these leeches are from broken families and hence have nowhere to go. BC sabki jindagi barbaad kar ke he rahenge and the prime targets are always UC Hindus, Sikhs with military backgrounds(parents) and Kashmiri Muslims. The largely non-aligned, non-partisan KM's are their primary targets, including women who are often hooked on to drugs and sex first before their grooming begins.
The profs are neck deep in this game.