You can seem like an alpha and be polite. Usually guys who are physically very strong, or who have fighting or combat background, generally can pull this off best for 2 reasons:
1. Because they know their worth against most of the other dudes present so they feel as on top of the wolf pack. Not in an obnoxious asshole kind of way. You just see it and feel it.
2. Because they know that there might be another guy there, just as relaxed and inconspicuous and polite who is stronger and/or better fighter than them. Hence the politeness and upfront respect.
1. Because they know their worth against most of the other dudes present so they feel as on top of the wolf pack. Not in an obnoxious asshole kind of way. You just see it and feel it.
2. Because they know that there might be another guy there, just as relaxed and inconspicuous and polite who is stronger and/or better fighter than them. Hence the politeness and upfront respect.