I would find two brothers having sex distasteful also....I would find two men having sex distasteful...however that is not a moral position, it is simply a personal preference. I can no more help how I feel about it as I can change whether I like a certain food or not.....
However, the fact that I find it distasteful is not the problem of the homosexual couple...it is my problem and it is one I need to deal with and this is where my morals over-ride my distaste, as I would never base a judgement on the individual or their relationship based on the fact that I don't like to watch men have sex....