Confusion is an important barrier to overcome when advocating engineered human longevity. For those folk who are not paying much attention to the topic - which is, sadly, 99.9% of the present roster of the human race - there's little apparent difference between advocacy for real, plausible scientific development and the nonsense of the "anti-aging" marketplace. It's pretty much all the same to them, and that's a big problem.
One of the long term projects for the advocacy community is to raise the general level of education and awareness, such that a far greater number of people do know that they should support SENS research and not the ramblings of the pill and potion vendors if they do have an interest in living longer. Not a small project, but we can all help.
Things become somewhat worse when we pull in religions and spirituality, however. To go along with the confusion created by the prodigious and often duplicitous output of "anti-aging" salespeople, there are entire armies of people who place immortality in the spiritual sense into the same bucket as life extension through science. They are even more confused - and you can find a good example in a recent article that shifts seamlessly between radical life extension through technology, the longevity of being famous, and Buddhist spirituality. All in the same category for that author.
Religious beliefs are, unfortunately, delusions. It's just the same as any dream of lazy immortality - such as the possibility that you are software in a simulation, a brain in a jar, or one of infinitely many copies in a universe of many parallel worlds. You shouldn't live your life banking on being a brain in a jar, and you shouldn't live your life banking on a supernatural continuation of your existence post-mortem. All that these comfortable beliefs give you is the chance to feel good while failing to achieve the material, real-world goals that will give you a greater chance at a far longer life. It's grand failure, while pretending to succeed.
While it's tempting to let the religious have their cozy refuge, that's no way to run a campaign of advocacy for scientific development, as noted at length by other authors:
As far as every experiment ever done is concerned, [the Dirac] equation is the correct description of how electrons behave at everyday energies. ... If you believe in an immaterial soul that interacts with our bodies, you need to believe that this equation is not right, even at everyday energies. There needs to be a new term (at minimum) on the right, representing how the soul interacts with electrons. (If that term doesn't exist, electrons will just go on their way as if there weren't any soul at all, and then what's the point?) So any respectable scientist who took this idea seriously would be asking - what form does that interaction take?
Nobody ever asks these questions out loud, possibly because of how silly they sound. Once you start asking them, the choice you are faced with becomes clear: either overthrow everything we think we have learned about modern physics, or distrust the stew of religious accounts/unreliable testimony/wishful thinking that makes people believe in the possibility of life after death. It's not a difficult decision, as scientific theory-choice goes.
We don't choose theories in a vacuum. We are allowed - indeed, required - to ask how claims about how the world works fit in with other things we know about how the world works. ... There's no reason to be agnostic about ideas that are dramatically incompatible with everything we know about modern science. Once we get over any reluctance to face reality on this issue, we can get down to the much more interesting questions of how human beings and consciousness really work.
The same goes for engineering longer lives for ourselves and our descendants. That worthy goal is fundamentally undermined by the widespread acceptance of supernatural immortality. The religious nature of your average human and human society is yet another hurdle to overcome - it won't be going away any time soon, given its origin in evolved human nature, but we have to find good ways to work around its effects.