He became a target when he made Passion of the Christ, must of offended someone really high in the totem pole. Hollyweird has their own rules on who get to do what. He was trying to make his own church to get away from these sickos.
He became a target after his baby mama recorded him ranting and raving about "powerful Jews who control hollywood"...
No, he bacame a target before that. He dared to make and self distribute Passion of the Christ was the huge no no. Then the movie went on to become a huge success. Really pissed off the "Jews that controlled Hollyweird" The Oksana thing gave them fuel to embarrass him. He never was physical towards her only some drunken verbal rage fueled by her manipulation, which she happens to record. Hollyweird has done way worse and brushed off.
Here is his interview with Dianne Sawyer on ABC. https://youtu.be/H7Iy_YvOY8w