A less charitable reading will assume that you're writing off the claim as nonsense because you think that biological immortality and uploading are nonsense as concepts, though your follow-up comment written after the downvoting shows that this isn't the case.

I assume people here know me enough not to jump to that conclusion about me, so I don't think it's a plausible explanation for the downvotes (and lack of compensating upvoting).

My leading hypothesis is still that people didn't like the rude nitpicking aspect of the comment, despite its other properties, but given the number of transhumanists on the site, it's very very bad to not be extremely wary of falling into the relevant affective death spirals, so this reason isn't a valid excuse.

On the other hand, maybe too few took notice of the comment for the voting pattern to be informative, hence escalation (I'd like to proceed all the way to a top-level post discussing the problem - not the particular comment of course - if not resolved to my satisfaction, although with all the writing up trouble it's never a guarantee).

The funny thing in this particular case is that spreading memetic noise about the availability of biological immortality in our lifetime can actually make it a more likely outcome by making people more aware of the need for anti-aging research effort.

I don't think it's a reasonable dichotomy (the supposedly better option, which it's probably not, is worse than some obvious third alternatives).