It's fine in theory to criticise the ethics of the idea alone, but there can be a limit to that.
If the CEO of a mining company has the "ingenious, un-PC idea" to increase mining profits by lobbying Congress and donating to sympathetic lawmakers to ease EPA regulations so he can dump mercury directly in the river, my ethical argument against the idea is that it damages the environment and the people in the communities, possibly for generations.
If his answer is "I know that, but I value profits more," what is left to discuss about the ethics of the idea? We agree on the facts of the matter.
All that's left is for me to say "I think your moral framework is very different from mine," which is really not that different from my saying "I think you are a bad person."
But can't you see the difference here? There is no argument that dumping mercury in a river is good for society, the environment or anything else. It's only "good" for this companies profits and even the real value there is a question given the impact on most people working there.
But extending human life? Maybe it will be bad. Maybe people will keep having children at the same rate and with no one dying anymore the whole planet is completely full of selfish people who don't care about others of the environment. Maybe only the rich will have access, block everyone else from getting it and control the world by simply out living anyone who is in their way.
But what comparable things do we actually see in history? In every country I'm aware of, once basic survival is taken mostly for granted people stop having kids as quickly and often as they can. In fact these days people often wait so long they depend on science to make birth even possible in their advanced age. And most people have, at most, 2 kids.
Imagine if we lived 10k years. Some people might say "well, lets have our kids right now so we can give up 18 years or so now and then have the rest to ourselves" but I suspect most people would say "what's the rush?". Some would even say "why invest 18+ years to extend my legacy to someone I can't control, can only marginally influence for a decade or two? In 10k years they're bound to solve death all-togher. I'll be my own legacy! And if, after 9,900 years they still haven't done it, I can always reproduce then". Imagine not wondering if there was a Troy, we could just ask the people who lived there. In society, we tend to be safe from some tragedy until most people who lived it are dead then we fall in the same trap again. What if they didn't die?
I say all that to say, it is not remotely obvious that extending human life is in the same category of behavior as dumping mercury in the river to make a few bucks so the consequences should not be the same or even similar.
Sure, life-extension is a nuanced question, but the topic under question is whether we should ever criticize the person presenting an "outside-the-box, maybe un-PC" idea, rather than criticize the idea itself.
My mining company example was much closer to the kinds of ideas that are actually pushed by people in the real world, quite frequently, more so than the article's anecdote about life-extension being criticized.
I'm saying that some people seem to pursue profits in such a way that they clearly have a moral framework that doesn't match mine, and arguing over the ethics of the idea with them is fruitless.
Did whoever it was at Volkswagen who had the bright idea to make cars have a system to detect when they were being tested, and change their emissions accordingly, really need someone to debate with about the ethics of the idea? I don't think that was a case of someone with a simple lack of knowledge of the ethical arguments.
These are the kinds of "innovations" people are coming up with in the real world, more-so than life-extension. People are going to create new apps that allow microloans with Bitcoin, with usurious rates, and market them to poor people. People are going to create dolls that listen to your kids and use the info to market toys to them. People are going to create devices to allow you to monitor your health, and sell the info to drug companies, or even to employers. There are going to be plenty of Bad Ideas where the people peddling them know the ethical arguments against them. At some point, we get to criticize the people coming up with these ideas as well.
On the other hand, people not only drive, but also oppose progress; as a smarter than me person (don't remember who it was) said: Science advances one funeral at a time (it's basically like evolution). If people stop dying (barring accidents), we'll basically stop advancing as well.
Aging eventually impairs the brain. If life extension is possible, it will have to protect pretty much all your organs from aging, and why would the brain be excluded?
Again, you're preseenting assumptions. We don't know that things will still work that way if people lived radically longer. You certainly don't know that well enough to shun people who try to find out.
If the CEO of a mining company has the "ingenious, un-PC idea" to increase mining profits by lobbying Congress and donating to sympathetic lawmakers to ease EPA regulations so he can dump mercury directly in the river, my ethical argument against the idea is that it damages the environment and the people in the communities, possibly for generations.
If his answer is "I know that, but I value profits more," what is left to discuss about the ethics of the idea? We agree on the facts of the matter.
All that's left is for me to say "I think your moral framework is very different from mine," which is really not that different from my saying "I think you are a bad person."