Is a young man considered undutiful to his parents if he refuses to marry a girl they choose for him, and this results in their anger and the young man leaving the home?

You are not religiously obligated to marry the girl your parents approve of. However, if she possesses good character, beauty, and religious devotion, and by marrying her you are showing dutifulness to your parents, we hope Allah will bless you. But if you refuse, you are not obligated to obey them, as their right to dutifulness (birr) is limited to what is beneficial for them and does not harm their son. Your refusal is not an act of disobedience (uquq) unless it is accompanied by harm, harshness, or leaving the home in anger, as uquq can occur with the slightest harm. We advise you to be gentle and kind to them, seek their pleasure, and ask for intercession from someone who holds a respected position with them.