Some people exploit vulnerable people without even realising it, and any attempts to be helpful can be seen as exploitative in the fullness of time. That being said, unscrupulous people will try to exploit emotional vulnerabilities for their own gratification or to extend control over people around them. Sexual predators, bullies and people who are themselves, in fact, vulnerable in one way or another, tend to try and exploit vulnerabilities they see in others. This might be a way for them to deflect from their own insecurities or perceived vulnerabilities. Manipulative psychopaths are well-known for their attempts to influence vulnerable people.
Vulnerability is a strength! For more content like this, Join happiness.