Why won't he talk to me?

Don't keep texting him. Find him and talk to him. Don't stalk him. Don't beat around the bush. Maybe he isn't good with conflict. That is common for people who came from divided homes. Conflict is good and leads to growth, but it must be processed and handled with growth and respect in mind. In other words, I want to grow, and I respect them, so I will discuss this with them in a manner that will lead to growth and leave them knowing I respect them, even if I don't agree with them.
He is disrespecting you by not responding. HE may even be holding a grudge, or allowing his pride to keep him from letting you know he sees your point. The only way you will ever know it to talk with him face-to-face and listen to his verbal, and non-verbal communications. If he can't meet your eyes, without you glaring at him, there is a reason, and he needs to deal with, and own up to whatever it is. For his own relational health and development, as well as for the health and development of your relationship.
Be patient and understanding. Don't judge what he says, no matter how ridiculous it may sound to you, it makes sense to him, for his own reasons. If you invest enough in him, you will find these things making sense to you as well. You may not like or agree with them, but you will find the understandable, under the circumstances he was experiencing when he made the decisions involved.