According to you, who do you want to sympathies in Boarding House?
I will sympothize Doran. Mrs.Mooney who had to face a lot of troubles in life, it might had been the reason for her patriachal ideology, (She dealt with moral problems ike a cleaver deals with meat) her intention to make some prosperous man marry her unfavourable daughter. (She watched the pair and kept her own counsel) It is a profit for mooneys who were belong to a lower social class whereas an entrapment for Doran.
Doran, in one side is trapped with exreme forces of religion. (priest magnified the issue.) And trapped with the social view. He was the one to blame, as he was a matured one in his mid thirties whereas Polly is still a teenager. Regardless of her illiteracy (I seen, I'd have known), her lower family background and that little vulgerity, he agreed to wed Polly, which is implied by the triumphant announcement by Ms.mooney, according to her, Doran wants to speak to Polly.
He flashbacks Polly was the one who initiated the relationship, but actually one can't clap using a single hand. He was utterly helpless, he cudnt runaway due to the fear of public disclosure and loosing is sound reputation. He couldnt shave for three days, he was anxious when stepping down to meet Mrs.Mooney. his trapped and helpless mindset generates sympothy on him.