Angel locked the feed, not wanting to give away the numbers over a public feed and not wanting to draw attention to his son. Connor might only be part vampire, but he doubted those who lived off fear and paranoia would quite see it that way. His son was capable of handling himself, Angel's aware, but he's a possessive person, which only serves to amplify those protective parental instincts.

"Four that I know of, myself included. Probably more who have been keeping their fangs under wraps."

Though he was unaware of the vampires from Mystic Falls, Virginia, he wasn't stupid. He just doesn't care enough to go looking for those who might be vampires.