Hello Somerset.
You've definitely been on a journey. I feel sad that you were misled by the type of people that we try to inform others about so they can avoid it. The sweatlodge you attended....they definitely pulled the wool over people's eyes. Modesty is indeed a quality exhibited in a traditional sweat and going on your time....is a big no no. However, you simply don't know what you don't know and to humble yourself in order to acknowledge mistakes is one of the roles we have as humans...you've done that and learned something valuable and that has steered you away from serious potential harm. I wish you the best in your continued good judgment.
As for the question regarding moon lodges/red tents. It's true that some tribes (not all by a long shot) have something that resembles this represented in their culture, it's again one of those things that is given a generic mystical "Native American" label and then reinterpreted by whoever is deciding to "teach".
On a quick google search you'll find many new age and pagan organizations and individuals that lay claim to what they do as a "moon lodge" and claim it gives them power. A more practical explanation about it is the belief in the need to separate individuals during this time to avoid the possibility of causing sickness or possibly hurting others. But again, this is a communal and tribal specific belief...not all tribes follow this way and among those that do, there are different schools of thought around it so please don't take my words as gospel. I'd encourage you to continue to follow your studies and you'll find there's a lot to learn about it. As for the person you mentioned that was facilitating...if they are charging money....then yes they are wrong. That's always the first and biggest clue and the whole purpose of this board.
Superdog