For anyone interested, the quote by Immanuel Kant is
Always recognize that human individuals are ends, and do not use them as a means to your end.
It's about treating people with dignity and respect, and not using them, because simply being human has an intrinsic value. So we should respect the inherent value of ourselves and others regardless of who or what they are and what they are going through.
Despite quoting Kant, Renesha goes on to say that it's okay for Elvin to treat her as a tool, use her as a means to an end... so I'm a little confused why tf Renesha is contradicting herself and what about the scene is supposed to be touching.