Stop allowing professionals to use Meetup to promote their profit-oriented services
I think it goes against the spirit of Meetup's original intention to have groups that require payment of $20, $30 or more per "meeting." Let's be honest, these people are using the well-established Meetup platform to promote their own business interests under the guise of facilitating togetherness and/or "community." It's unethical and confusing for participants. You should not allow it.
You assume that these people aren't meeting in a decent location, as my Meetup does. You're also assuming that they aren't providing food/drink during their Meetup, as mine does. Lastly you seem to miss that maybe, just maybe, they bring in guest speakers for whom they compensate for their time, at their Meetups, like my Meetup does.
I'm just guessing that these possibilities are far reaching and 'unethical'. On the other hand, perhaps you're just upset that you can't afford to attend their Meetups and came in here to voice your opinion that their Meetup should be FREE so you could attend.