I totally understand your sentiments. I would be angry too if a bureaucrat had the power to stop my parents from visiting me. Luckily my parents are triple citizens like me and although they live in Canada, they have every right to come and visit me in the US whenever they feel like.
With regards to your next move. This is what I would advise. Wait for 6 months. Then ask one of your parents to apply for a visa. If you father still works in India, ask the mother to apply for a visa. Your father staying behind in India will work for her. If she is issued a visa (I hope so), then ask your father to apply. If he too gets it, good. Both of them can visit you. If not, ask your mother to visit you. After her visit, she will ofcourse return to India. Then ask your father to re-apply once she is back in India. Seeing that you mother visited (and returned in time) the US, the consul may ease his/her fear of your parents not returning to India and may issue your father a visa too. I wish both of them good luck!!!
Don't give up. Planning and perseverance is the key. Indian authorities made me wait 20 months for a visit visa while the did a background check on me. However since I was keen to see my grandfather's house (the house where my father was born) in "Purani Dilli", I never gave up and eventually I was issued a single entry visa.