I can intentionally do lots of things, some of which cause entanglement and "collapse", and some of which don't. I'd say to them that it still seems like the conscious intent isn't what's important.

If you'd like to substitute a better picture for the layperson, I'd go with "disturbing the system causes collapse". (Where "disturb" is really just a nontechnical way of saying "entangle with the environment.") Then it's clear that conscious observation (which involves disturbing the system somehow to get your measurement) will cause (apparent) collapse, but doesn't do so in a special depends-on-consciousness way. And if they want a precise definition of "disturb", you can get into the not-too-difficult math of superposition and entanglement.

Perhaps that extremely simple systems, that no one would consider conscious, can also "cause collapse"? It doesn't take much: just entangle the superposed state with another particle - then when you measure, canceling can't occur and you perceive a randomly collapsed wavefunction. The important thing is the entangling, not the fact that you're conscious: measuring a superposed state (i.e. entangling your mind with it) will do the trick, but it's entirely unnecessary.

I used to believe the consciousness-causes-collapse idea, and it was quite a relief when I realized it doesn't work like that.

Upvoted for noticing your confusion. At least two possible reasons come to mind:

Explanation 1: Luke has made many solid contributions in the past, and such contributors' comments tend to receive more upvotes than others' do, just by a kind of halo effect: "Luke's other posts are good, so he's a good rationalist, so this comment of his must be good too." I don't know how true this is: I've heard the idea suggested by other people here, but I've also seen several examples of top contributors receiving well-deserved downvotes in some cases.

Explanation 2: Luke's comment is genuinely more deserving of upvotes, since rysade's comment uses phrases like "I think" and "subtly changing", which downplay commitment and measurability, respectively, while Luke's comment indicates an explicit change he has already made. Again, I can't really speak for the people who upvoted Luke's comment (not even being one of them myself), but it seems plausible that this is at least one force at work in the disparity.

I don't know how much of each of these two hypotheses is truly at work here, or if there's something else going on that I've missed. (It's easy to come up with what are in my opinion less likely scenarios: Luke has made several phantom accounts to upvote his own comments and/or downvote others' similar comments, or someone else holds a grudge against rysade, etc.)