There is a well regarded computer bulletin board called Craigslist.org, where people commonly post announcements and leave messages.
Craigslist has a site for Denver. You can post your info there
I advise posting both on 'General Community' and in the 'psychology' and 'spirituality' forums. (for the latter you need to register--easy to do)
Keep your post brief, courteous and stress the facts. Give the URL to the other thread on the LGATs forum and give LGATs to any news articles on the group. As they said on the old cop TV show Dragnet--'Just the facts'.
By staying brief and courteous, you cannot as easily be accused of being either defamatory or inflammatory.
Be prepared to cope with shrill accusations that you are negative and cynical. The New Age/yoga crowd specialize in this. Ignore it and forge ahead.
If your posts are flagged (that is enough people vote to remove them--kind of like Survivor) courteously inform the webmaster via the 'feedback' forum that there is a trend where people can advertise worrisome programs yet anyone offering warnings based on conscientious documentation is getting flagged, producing a context that keeps people from getting access to balanced information needed for a fully informed decision.