well, this was an invited guest. by virtue of a committee or group conscience vote? it seems to me since his "message" was not only flawed in it's facts, but also skewed towards HIS addiction "cure" rate, perhaps this should be brought up for a group conscience, or at a business/committee meeting? no matter how much we may as individuals take umbrage with what someone else shares at a meeting, we are no greater than the group....but as a member OF the group we have the freedom to share our concerns WITH the group.
also demonstrates why we need to be so careful when inviting "outsiders" or professional to "speak" at meetings. it doesn't sound like he was sharing his ES&H. good for you for noticing the discrepancies and CARING about how that might impact your group.