Extreme obesity

WLS surgery does not work. Almost everyone who survives the surgery regains the weight.

He should be ashamed of himself for putting his own desire to see her fatter ahead of her unhappiness at her current weight

You should be ashamed of yourself for behaving as though the only issue at play here is that the medical establishment is pushing for her to lose weight through drastic measures (though that is definitely a major issue).

Someone else's body and their happiness is far more important than how attracted you are to them. If you wouldn't be able to have a happy relationship with someone because they're unhappy and decide to not be massively huge, they deserve better than you anyway.

The only problem with that is that not everyone who wants to become fat can become fat, and not everyone who wants to be thin can become thin.

In itself it is not wrong to be turned by a very big SSBBW, as long as you can find someone like minded who is comfortable the way she is.

It is wrong though if you put your own sexual desires before the mental and physical well being of your partner, it is wrong to choose a partner only for her weight and not because you genuinely love her for the rest of her as well.

Of course it is difficult if you are only attracted to SSBBWs and they loose so much weight that the physical attraction is gone, but that is the reality of being an FA. You have to ask yourself if your love is strong enough to be with a partner if she lost a lot of weight and be open with her about that. If this is really important for you, you have to look for a likeminded partner.

They deserve someone more suitable perhaps. Saying that one persons desires overrides another persons desires is the thing you were attempting to avoid but you said it anyway.

This is a fat acceptance and enjoyment site. The reasons many fat people do not enjoy being fat is to do with how they see themselves through the eyes of others. People have been programmed to hate fat so even some fat people hate fat and they know other people hate them for it.

WLS is justified on health grounds but is motivated out of this hate of fat. The health justification is false because it's more dangerous than actually staying fat.

Accept what is unchangeable and change what is unacceptable.

No, I pretty much straight up said that one person's desires regarding what they want for themselves is more important than another person's sexual desires regarding the first person.

Or, more simply:

Your boner is not as important as what she wants to do with her life.

Why is this something that has to be argued?