If this individual is someone who enjoys wine responsibly it might be suggested that it would be even more responsible to enjoy it a bit more discretely...not to hide anything...just to avoid upsetting those who would consider this hypocritical.

Unfortunately this Bible study leader has chosen to drink and get buzzed in the presence of others in his group and has lost credibility as a Christian teacher.

I get this...I don't think Christians drinking wine responsibly is sinful...but catching a buzz in the presence of students...hmmmmm. Where is the balance here?