That is a very poor example. Simply having "a beer" with a meal is not a sin no matter who may say it is, the sin would come from an over indulgent drunken binge, which would more than likely be regretted later and that would be where the repentance may come in (and fit nicely in my opinion). I seriously doubt you would feel "conviction" over a single beer or two. Another fine example of that scarecrow that lives around here.
And Willie I believe if I understood him was asking "if his having one beer which didn't violate his own personal beliefs - should he not have a beer if other people "think" it's a sin to drink one beer"?