Why does the drink change it?

Why does the type of drink you have change the "meeting"?  I had plans to meet an old co-worker.  We were going to meet for wine, my old co-work recently took a job close to where I work.  So we thought we would check out this great wine store that does tastings and you can order a bottle and enjoy!  Of course life got busy and my plans with her fell through.  My current co-worker heard me talking about my "ex" (that is what we call our previous co-workers) and he said he was getting jealous.  So I told him that when (and if) he left teaching I would meet him for wine.  He said he didn't know if he would feel weired or not.  I laughed and couldn't figure out why he would feel weired (my sister, who I was on the phone with couldn't understand either).  I asked if we met for a beer would that change it, he said "absolutely, then it would be fine". 
Why does the drink change it?
My Theory (and my sisters):

• You rarely see/hear of two guys meeting for wine
• While men enjoy wine, it is thought of to be more of a woman's drink and therefore the man would be accommodating the woman
• Wine is sensual (so two people of the opposite sex meeting for wine who are married to other people...)
• Meeting for "beer" sounds cooler...