People do things you don't like all the time. Look at politics and how people argue and try to change other's opinions to their own. Disagreeing on a decision over which you are not the decision maker causes more arguments than it's worth.
It's common for someone to disagree with your decisions. In general, I think we seek to make the best decisions for our lives, and everyone may not like those choices. Folks will him and haw and fight to change your point of view. Rather than coaxing you into a new way of thinking, the fighting often drives you farther away from the arguer's vision. No one likes to be wrong.
This kind of fighting is a useless waste of energy when all it takes is agreeing to disagree. This is where the difference between accepting and agreeing comes into play. You may not agree with what someone you love is doing, but you can choose to accept it. I'm not talking about extreme cases like drug abuse breaking the law or alcoholism, but general life decisions like your lifestyle, the way your fashion sense and hobbies.
The trouble with acceptance is that it feels like you are condoning what you do not approve of. If you condone it, then you feel like a hypocrite, but that is the farthest thing from the truth. Accepting someone else for who that person is even if you do not agree with their personal choices is a sign of love and can be quite liberating. When you choose acceptance, you own the fact that you have no control over that person's thoughts, words or actions and you show that person love by accepting the person as he or she is.
I've found myself on both sides of this scenario and it is exhausting to try to change another person or fight being changed. Let's just show one another love through acceptance because you can!