First, the hunter calls Phoenix "Granny." She is very old and this might have been a term of endearment. But given the hunter's overall treatment of Phoenix, the term "Granny" is probably intended with condescension. He does help her up, but he also belittles her. He treats her like a child:
I know you old colored people! Wouldn't miss going to town to see Santa Claus!
In his ignorance, he assumes she is simple-minded. It would never occur to him that she is a clever, determined individual. Phoenix manages to steal a nickel that falls out of his pocket. When he points the gun in her face, she is stoic and shows her courage. He then lies and says he'd give her some money if he had any. Everything about the hunter's behavior with Phoenix shows his pathetic attempts to assert his superiority. He helps her up but treats her like a child. He pointlessly aims his gun at her to test his ability to intimidate. His rudeness is based upon racism and ignorance. Phoenix treats this like the any other hindrance on her journey: just another obstacle to overcome.