As for the people hurling personal insults and claiming that the right to receive should be based on the (hypothetical) commitment to give, why do you believe that this is the only time where this should be the case?
Let’s look at a different scenario. Let’s say that you have IVF on the NHS, you have treatment and produce eggs which result in ten embryos. You have one put back leaving nine embryos. Shouldn’t it be argued then that you should donate those embryos to couples who do not have the ability to have their own biological children and that if you say no then you shouldn’t be entitled to treatment? After all, an embryo is just a cell, no?
Or as I stated up-thread, you’re on benefits and have never worked. As a result you’ve never paid tax and national insurance and have therefore never contributed to the NHS. Why should you be entitled to receive life saving treatment then? Or should it be that the more tax you pay the greater service you are entitled to? It’s no different is it? Apart from the fact that it’s very easy to sit and make judgements on situations when you’re never likely to be in them. It’s quite easy to wish someone dead (and let’s be honest here, by saying people shouldn’t be eligible for donated organs you are wishing them dead) when it’s not you or one of yours you’re wishing death for.
Whereas most of us could fall on bad luck. Smoking caused you to have a heart attack? Sorry, no treatment, in fact by declaring yourself a smoker you should be removed from any list which allows you treatment for lung or heart disease. Similarly if your BMI is above a certain number or your weight is high you shouldn’t be entitled to treatment for heart disease. Eat too much sugar? No entitlement to insulin. The reality is that around 65% of cancers are preventable with lifestyle choices, therefore we could cure the people whose cancer is purely a matter of bad luck rather than those who say, didn’t go for their last routine sneer, or mamogram, or who didn’t have the HPV jab. If you’re a smoker then sorry, no treatment for any kind of cancer. Do you have a mobile phone? Well that probably contributed, so nope, off the list.
Every single one of us will have at one point done something which someone else could frown upon in medical terms as it could cause medical conditions. But it’s far easier to have a pop at those whose shoes you never imagine yourself in. After all, on the whole organ donation is something which happens to other people so you don’t have to actually think of it as potentially being one of your children you are hoping will die even if they would never have the opportunity to donate anyway.