So you have no problem charging for rendering services for groups like cancer survivors, child molestation survivors, groups that relates to mental, emotional and physical sufferings
None whatsoever. Meetup.com does not owe these people anything. Their bad luck gives them no claim on the time or resources of the owners of meetup.com
make them pay for a service like meetup.com so they can set up support groups such as the ones mentioned above?
Again, nobody is making them pay. A service is being offered for a stated price. Those who wish to avail of the service can do so if and only if they are willing to pay the agreed price.
Sounds like profiting off the misery of others.
No, it's profiting from providing a service.
Perhaps you think if a "survivors" group wants to meet up, they should also be entitled to hire a room for free, and presumably have it fully catered for free. Maybe free phone calls as well. Hell, why should they have to pay for anything after what they've been through?