• When someone tells you a normally hidden consequence of what you're doing, you don't tell them off.
• The norm is to give a full answer. If you don't, say you will elaborate later, give a summary, or say it's too long to explain. Don't unilaterally defect.
• If you defect, you're telling people your time is more precious than theirs. This is rude.
• In particular, you bother to post on LW in the first place. "Near-strangers deserve no information from me" is unfair.
• We want to promote pointing out specific problems. A rant against memetics and signalling games in general is a bad answer to specific criticism.

that a small amount of information when requested is significantly better than no information

That's assuming that the information is correct. It could also be wrong or misleading, in which case it would be better not to receive it. While "Do you mean whole brain emulation?" "No" doesn't fall into this category, claims like "we know how to build AGI" are definitely claims that could be wrong, and are indeed generally considered to be wrong.

Unless you provide a reasonable argument or reason for why we should believe such a claim, anyone maintaining any epistemic hygiene standards (or common sense, for that matter) will be forced to ignore it. Therefore such comments only serve as a distraction, providing no useful value but taking up space and attention.

If I were to comment on conversations and tell people that 2 + 2 = 5 and then refuse to provide any justification when asked, people would quite reasonably conclude that I was a troll, too.

Anyway, I am aware that people do not seem to understand that a small amount of information when requested is significantly better than no information, and I am aware that there are no affordances that would allow people to take the 3 seconds of reflection that would be necessary to realize this after realizing that their implicit expectations about how much information they deserve to receive from near-anonymous people are probably not based on any sort of explicitly justified or explicitly reflected-upon analysis.

When I notice myself writing a sentence like that, I drop it and do something else. Maybe I would come back to it later, but not less than 24 hours later.