I think the impulse to promote all meetups was a good idea but now adding to much noise to the "PROMOTED" feed. Of the 10 "PROMOTED" feeds 8 are adverts for meetups.
I propose adding Meetups to the navigation bar and only adding them to "PROMOTED" when they are especially significant; for example have a special speaker and might draw attention from people who are out of town.
You are probably correct at this. A structural change to the website so that meetups and actual posts are placed seperate but are equally visible would probably be best.