Xiumin’s Agency Claims KBS Blocked His "Music Bank" Appearance Due To SM + KBS Denies
This confirms why Snsd members under other labels do not do music in Korea. Snsd is also the only group with members not signed to SM that participated in their 30th anniversary event. Now it's clear that it's because they don't do music in Korea. They are not directly competing with other SM idols so they keep a healthy relationship with SM. That's why Jessica too can't promote on Korean TV and radio.
I hope it's a one time Xiumin only issue and not a full-time CBX blacklist. SM is so trashy.