Can I use tears to make my point?
That sounds manipulative. Do you think that the tears will work?
Yes, it usually does the trick.
It seems a little ingenuine to cry on purpose. It seems a little wrong to manipulate people to feel a certain way.
It is not. Crying is a good way to express your emotions when you don't know how to do it otherwise.
But other people do not feel that way. Tears make people feel a certain way and you should stop using them to make a point.