@Zay- of course he/she "should", but neither us nor them live in a perfect world where everyone does what they should.
when you say "he" are you referring to the male at the very end of the chapter? if thats the case, then yes, obviously he should conduct himself more decently, as far as i can tell (read that part again) he seems to be a knight of the family, below or at a similar rank as the shield lady. he seems to be the "strength seeker" kind of guy, wanting to fight the unknown guy who seems to be strong (totally making assumtions based on that panel and his appareance). again, completely rude and if i were the mc i would say something on the lines of "and why should i?" and leave, if the guy atacks just plummet him.
If the mc is atacked by the guy you sure can bet i expect the mc to absolutely deck the guy, no mercy other than his life.
if you werent referring him, could you specify who please?