Telling someone to leave the property is de facto not provoking the person.
I’ve been involved in a shooting case like this - I got an education in this from my attorney, came out just fine. If you live in Texas and you think this about the self defense/property defense laws, I strongly suggest you go ask a defense attorney to clarify the law for you.
It is certainly possible to tell somebody to leave one's property in a manner which does not provoke them. However the defendant did not choose one of those ways.