In the Humanities areas of Academia (often where "communications" resides) there can be a huge disconnect between technical expertese (sometimes described derisively as "skills") and the more conceptual understandings of the media.
If this Prof is really so far out of it, challenging him in front of the class will not help matters. Often people who are out of their depth will do everything they can to deny it and will end up hating you for pointing it out. If they have to be the "sage on the stage", anything that detracts from that will be a direct challenge.
Is this person assigned as your direct supervisor or is your job description to support the Lab as an academic resource for the Department? If the latter is the case, who is your real supervisor? Have a conversation with them (Chair of the Department?). In all likelyhood, they are aware of the gaps. If not, you have done something to address the issue. If nothing else, behaving in a professional and engaged manner keeps the discussion civil and may bring about some useful changes.