Our Meetup has been operating for many years now. We have 700+ members on record but 100+ are active due to the nature of our group. We are a private meetup offering support therefore, our members are screened before they are accepted to ensure they are joining for the right reason and not confusing us with a singles group. We have 3 people on the leadership team and a social events organizer. We meet monthly to discuss specific topics and also try to get guest speakers. We also meet weekly in smaller groups. The feedback we get is wonderful however, we have had to deal with difficult members and have had to ban a select few but it is done after speaking with the person and giving a second chance. We cannot please everyone nor can we help everyone who comes to us.
There are many Meetups out there that anyone can start with their own agenda. I don't think Meetup overall should be blamed; it is the individual organizers who give it a bad rep.