The answer is that<em> by doing so he would violate the very customs Okonkwo is trying to preserve</em>, meaning that instead of being the bigger person he is becoming what he detests the most.
Another option would be that the use of violence would make him become the father he has always hated.
The word that is an example of comparative degree adjective is louder. The comparative degree adjective shows that there are two objects that are in comparison while the superlative is when there are three or more items being compared.
