Try this. Show them the hard facts on bronies. This survey was done to find what the audience ACTUALLY consists of; and disproves many of the stereotypes and myths assumed by those who are skeptical. If they will not sit down and read it, then they are clearly too single minded to have the decency of at least LEARNING SOMETHING versus making up stupid opinions that aren't true. And make sure you tell them that if they refuse, tell them that they have no right to formulate any opinions on something they have no knowledge about. http://www.bronystudy.com/id9.html
There is a good chance they'll refuse to look at it, but it's worth a shot. I really hate to hear that your dad is throwing "gay" at you in that way. Ugh. It makes me a little sick inside.
Well my point is that if they do refuse, they have no right in making opinions in something they have no knowledge of... But its so hard to stop people from being stereotypical, but it is worth a try.
To avoid further argument, I will simply state that we should allow David to choose his own path, and we must respect his decision. If he chooses to fight, or not to, that is up to him. We are simply here to comfort him and to provide advice for him. We have done that, so let us let him decide what to do next.
Danvid, I'm not saying that this is the right thing to do, but I would fight for my parents acceptance. I do believe that my own parents would support me whoever I choosed to be though.