If you don’t have the discipline to not drink too much then no a Christian shouldn’t. It’s not about the alcohol but the discipline. If you can’t handle it you shouldn’t do it.
No, Christians should be showing Gods love. This can be by questioning another believers vision in Biblical matters. But arguing is not the way to show Gods love.
Yes it is a sin, also see Romans 1:27 but everyone knows that us Christians see it that way.
Do they know that Jesus stands above all sins and died for ALL sins.
John 3:16. Live it.
How does a person know if they are a true Christian?
I hope I am and I hope my way of life shows my devotion to Christ. But only God knows if I am doing His will.
All I can do is ask Him to guide me to do His will.