Sometimes people rage over their values to signal just how much they care about them.
This is counter-productive.
In the long run, being patient should be the winning strategy. After all, people are only very rarely persuaded of anything on the spot. All you can do is be the best spokesperson for your position that you possibly can be. You might plant some seeds in their head - as Peter Singer did in mine - or just break their stereotype about what someone that holds your view is like.
Remaining calm might make it seem like you care less but it's the more effective strategy. If you really care about maximizing utility then you should keep in mind that you are playing a long term game and that being patient with those that disagree with you will do more good than will lashing out at them to signal how much you care.