Not sure if you, Peter Singer, will see this but if you do I'd like to say thank you for posting this, my thoughts exactly on all issues. Thank you for coming out and writing this article.

-It is not good enough for anyone to say "I can't help being obese/a smoker/a drug addict/an abuser." You should make a conscious decision to stop, even if it means to get help. Would it be okay if I said "I cannot help being violent, I am just addicted to bashing people up." No. If I knew it was wrong I'd go get help from anger management. Same thing.

-I am that slight Asian woman (figuritively speaking) with overweight bags and have to pay excess fees, when my co-passenger doesn't have to even though he himself weighs more than my luggage and me. In fact I am not even 40kg. Not fair, because ultimately airlines provide a service, their service is to carry a load, and there is only so much load it can carry, and will not and should not discriminate where the load comes from. Each ticket/seat should be allocated a certain weight and that is your combined weight. Go over pay more, simple. That way people travelling together can even share the load, because at the end of the day, a 40 kg person won't be able to carry 100kg worth of luggage anyway.

This article was linked on this question and I provided an answer here with reasoning behind it: https://www.quora.com/Is-it-right-to-charge-heavier-people-more-for-flying/answer/Stephanie-Qiao-1