Brutus's words appeal to logos because he made sentences that are convincing with logic in murdering Caesar. On line 15, Brutus said "It is the bright day that brings forth the adder" implies that evil can come from good, just as poisonous snakes tend to come out into the open on bright sunny days; the reason why we need to kill Caesar.
The moral choices Cassius and Brutus has made are killing Caesar, and betrayal. Because of Cassius loyalty to Pompey, so