ResetEra isn't just a social media platform on a technical level - it's on the most literal level. Replies in threads are just like replies in tweets or comments on insta photos or facebook posts.
You don't come to ResetEra to look at the website design. You come to obtain information and opinions. It's the same base-content level of any *popular* social media platform like Twitter, Instagram, FB etc. It is what you make it.
If you don't "get" why people like Twitter/Insta etc but "get" why people like forums, it's more due to you having more experience with forum format than short-form content like Twitter/Insta and the different requirements to customise your experience.
ResetEra already customises your Forum experience by offering you a forum dedicated to a specific subject you're interested in. Which means there is already a huge host of content you're interested in from the get go making it an interesting and engaging platform you want to interact with. Regardless of "how do i wipe my ass" threads or not, the literal community is already one you understand, interact with, and value/respect.
Twitter/Insta, on the other hand, requires some more upfront work. You don't get that content handed to you from the get-go without putting effort into who you follow and learning how the tags work. It still offers insightful and interesting content but you have to put slightly more effort into finding it. And the platforms tend to pump out what's popular.
In the case of instagram, hot models in bikinis is super popular. Which is why - for new users - your explore feed is full of them. It won't customise down until you stop looking at that content and only look at certain types. My explore feed is now filled with mostly gaming related content, because that's what I look at, on top of some other hobby things I follow. It's customised itself to what I like the most. Twitter also suggests people who are into games mostly for me after seeing who I follow and content I post.
For example, if you followed everyone on ResetEra on Twitter & Insta, you'd probably find near-identical content on top of some more personable content.
There's a difference between these social media platforms but ResetEra is a social media platform. Just because people write long form here, compared to selfies on insta, doesn't make it more "noble" or "important". It just means you relate to it more.