As someone who rarely consumed entertainment--except when he was a child and obsessed with the knight cartoon--Kar had little knowledge of showbiz.
He didn't know what a harsh place it was behind all the glitter and glamour. But then again, people thought it was nice being an esper with all their majestic power without seeing the dangerous aspect of risking their life. Perhaps, things weren't very different in all aspects of society, after all.
Kar had wanted to see what those hate comments toward Byul was like, but Byul warned him never to check that stuff out with a glare. That was cute, so Kar folded immediately.
But he was still curious, so he asked his sister. Instead of answering, Lucy asked him if he had watched Byul's works and scolded him when he said he hadn't. A few minutes later, his commlink was bombarded with links to the platforms where Kar could watch Byul's works--including the one where Byul was only a cameo.