the fact that you can't remove hubs, or "downvote", helps remove that mentality. Also, the continuous efforts of users to have quality content and quality discussion is a lynch-pin.
Trying to nail down better how I feel about comment hubwheels: But if I go to https://hubski.com/user?id=coffeesp00ns , I see both shared and submitted posts. Comments? Just submitted. When I'm scanning over the comments for a post, I don't see which comments people I'm following thought were interesting. I find variably full hubs. The chatter page is nice, but I'd like to see more. I feel like there are lots of interesting conversations that I missed because they weren't badged, and I didn't find the post they happened under interesting enough to click. The culture around the button might be different, but the button itself feels the same to me. I might try and vote up comments in a less knee jerk way on hubski, but I still think in terms of voting.
a note about chatter and global: You can, in the mid-upper right corner, see a filter for amount of Hubspokes (is that what we're calling them these days? catchy names are mostly irrelevant). This also works for #tags. Want to explore conversations you might have missed? all three of these are great places to go. Another cool note is that you can see who shared that post, and who shared it with you, by clicking on the number next to "Shared By" on the post's page. I generally agree with your sentiment regarding comment shares - Most of the differences come from user mindset. However (and I preface this by saying I'm not a coder or on the hubski team), I have noticed that new and rising comments are given more preference in on-page order than highly spoked comments are. Also, after 8 spokes, the amount of shares is visually irrelevant. This helps remove the psychology of "winning" opinions, or "winning" numbers of votes - after a certain point, it's all the same. Of course, if you want to get rid of all of that information, you can just use Zen Mode.