Frankly I think that Quora has probably run the numbers on this because they’ve been using this tactic for months already.
I’m also getting a lot of these sharing and what if posts, but contrary to you I often find them interesting and click on them, even though, yes, it’s not what I initially had signed up for to view on Quora.
To me it’s an interesting take, as previously Quora was to me a pure search engine for questions I already had. I am never browsing the site or topics on a regular basis.
But this external hook is every now and then powerful enough to make me come to the platform and read these posts and then end up reading something related. It’s not something bad. If it was I’d unsubscribe. Easy as that.