You should always be kind to people on the internet
Marc makes videos on YouTube for a living, and his viewers didn't like his last video.
Marc wants to respond to his viewers.
Marc tells his viewers that he made a mistake and that he'll listen to them more.
Marc tells his viewers that there's a reason they're not successful.
Marc's supporters feel closer to him, and Marc feels more humble.
Marc loses subscribers, and he hurts the feelings of his supporters.