Ultimately, it is because we like them. More than any single quality, we trust people we like.
Even after some celebrities make public mistakes and give us reasons not to trust them, after awhile we just forget about it and begin to trust them as if nothing happened. This happens a lot with NFL football players. A numerous amount of players were charged with domestic violence to their girlfriends/ wives. It will be a big headline and everyone on social media will freak out about it for about a few weeks, and than eventually it fades out and we continue to support their social media and social image as if it didnt even happen.