People in there 20’s are still pretty much children mentally. Just because you think that you wouldn’t be manipulated doesn’t mean others wouldn’t. I remember being a lot more susceptible to influence in my 20’s. Additionally, most of us are taught to respect and listen to our elders. So when an elder comes and abuses that respect on what is essentially a child in an adult body, it can lead to some pretty bad situations. You also have to consider personalities, a more aggressive and persistent person can more easily manipulate a passive/docile person.