Just respect each others opinion. You cannot force bitcoin to others as well as they cannot force their hatred of bitcoin to you. Just listen, state your point and move on. There is no point in listening more if you already made your mind about bitcoin.
it is easy for some one to naturally hate something they do not understand or never heard of and honestly you can not force them to have a change of heart so its definately best to respect their opinion and maybe one day they will come around.
Personally I don like to argue especially to those that have such a strong feelings about something so it is better for you to leave this person alone and keep benefiting your self through the use of bitcoin.