In October of 2022, Meetup.com removed the “comment” section at the bottom of events and replaced it with a “chat” feature.
The new chat feature does not email the organizer when a new chat message was posted.  If you post a “chat” to the organizer, they won’t know.  Do not rely on the Chat feature to contact organizers.  It also doesn’t notify you that a question has been answered.
I contacted Meetup about this, and they replied:
Our notifications system does not send email notifications when new event chat posts are made. Instead, you’ll receive on-site notifications (under the Bell icon when you log into your Meetup account) and push notifications if you have the Meetup app installed on your mobile device.”
If you need to contact an event organizer, please use the “contact” page on their profile, or you can email me at [email protected].  If you post a message in “chat”, it is possible your message will not be noticed. 🙁
Not sure why meetup made this change.  I assume it’s the same reason they removed waitlists from paid events and turn off email notifications if you install their phone app: to reduce the server load and bandwidth costs of sending out emails.  Or the new owners of Meetup do not use email, and only chat, and think we should do the same?
Please note, required FTC Legal Disclaimer: HoustonPhotowalks uses affiliate marketing and advertising to generate revenue for our budget and the organizers who run the group. This money is used to pay Meetup.com fees, website hosting fees, classroom fees, teaching fees, donations to museums and venues, provide bottles of water when possible, compensate organizers for their time, etc. When you click links, the HoustonPhotowalks organization may receive a fee when you purchase a product or service.