"Youtube" itself is not a source of information. It is a site where people post videos. Journalists post videos on Youtube through BBC, Economist, Washington Post, Nightline/PBS, etc...

Does their posting content on Youtube make them less credible?

Judge the originator of the content, not who hosts it.

Might as well go "Ah yes, the internet. A trusted source of information."

That's how shallow your retort is.