Everyone has a right to want what they want or be attracted to who they are attracted to. The problem, I think, comes when people have standards that are niche. If you want something that is rare, you are going to have a MUCH harder time finding that someone, regardless whether you are a certain race, a certain height, a certain weight or whatever.
This is where I suggest expanding their options. NOT lowering their standards or completely changing them, but how do you really know that what you think is your "type" actually isn't your type and that is why you are having trouble dating or staying in a relationship. You never know who you will fall in love with, so what's the harm in going outside that "type." Worst case scenario, maybe you make some it seems that if you are overweight the expectation is you are supposed to take what you can get and have little to no standards… do you think thats accurate ? Harsh but true? Or ridiculous, why should weight have anything to do with it?