What he means is that the channel started to remove all soundtracks from first-party Nintendo games (soundtracks from franchises like Mario, Zelda, Xenoblade, etc). So you'll still find music there, it's just that you won't be expecting music from Nintendo games there due to Nintendo's strict content guidelines. Here's what they had to say.
We are removing all videos containing music owned by Nintendo, since they have finally begun to block their content on our channel. This is a fair warning, so we are acting accordingly to avoid copyright strikes. We don't want another situation like when Smash Ultimate was leaked 2 weeks early. We will no longer upload Nintendo content.

test