It's like saying the average Hacker News user doesn't know what a computer is. You're picking an extremist, extremely small amount of users as an "average," despite them being nothing close to it.
https://worldheritagepostorganization.tumblr.com/post/674066...
But most of them have left now. I don't think you remember the spirit of the site properly if you think people on there are doing, like, normal stuff that makes sense.
(Remember in 2017 when a user turned out to be faking having HIV so they wouldn't be cancelled for writing real people fanfic about Lin Manuel Miranda? And they were called out by someone else who wrote real people fanfic about him where he was a cannibal?)
The period you're describing was several years after Marco left. And besides, David was technically the sole "founder" (see e.g. [1]). In any case, David was ultimately responsible for the product direction.
I don't mean to minimize Marco's contributions in any way, as his efforts were absolutely massive and utterly essential to Tumblr's success. But with respect to the community and culture, product direction matters a lot more than the backend implementation in this context. (And I say this despite being one of Tumblr's first backend engineers myself!)
