I think this comes down to two things though! These are the posts that have been around the longest and as such have accumulated a strong reputation, by voting on these posts people are chasing curation rewards... content doesn't matter to them! As steemit matures we'll see a shift away from this behaviour. I think people will get bored of chasing curation points and leave or start writing!
The support I have recieved within the steemstem community by some of the largest posters in the science field has been just amazing!
Thanks for the discourse :)