The difference is, weight is mostly a controllable attribute, while height is not. Also, I think most people find fat people to be unattractive.
You could always pay for a height increase surgery.
lol
If we are using that logic, we can just abolish racism right now. Since people just can't help themselves but to be racist toward varying colors, let's just all get skin pigmentation and plastic surgery so we all look the same.
It's not the exact same thing as height, I know, but there are similarities in both being inherent, uncontrollable attributes..
Point is, should you have to change a part of you that you do not have control over?
To say you have no control over your height isn't completely correct as many physical attribute(like height) can be changed via surgery.
I wouldn't personally get surgery to alter my appearance because I'm fine with it. But if it is a problem for you maybe you should consider surgery. ---