This is as much about culture/tradition and the large influx of triathletes into the open water swim community over the past few years. People don't like change and a large group of newcomers who aren't familiar with culture/tradition of a sport can ruffle feathers.
I make accommodations for triathletes who want to wear wetsuits at open water swims I race direct. Typically, the swims are non-wetsuit if you want to be in the running for prizes but you can wear a wetsuit if you want.
The tradition and culture of open water swimming particularly around the Triple Crown is largely driven by how Capt. Webb (1875) crossed the English Channel with minimal support and without a wetsuit. There was another swimmer that completed the crossing before Webb, but he used buoyancy. Webb was the first successful un-aided crossing and that's where the tradition started.
The Triple Crown is a large undertaking. It is 3 swims - The Catalina Channel Swim, The Manhattan Island Marathon Swim (20 Bridges) and the English Channel. I'm currently working with an athlete who is going to try to complete the Triple Crown (currently less than 300 people) over the next few years. He got his slot for the English Channel in 2025, he'll swim MIMS this summer and Catalina next summer. But to be recognized as completing the Triple Crown they are all non-wetsuits swims. For most of them you have to have a validated swim of 6 hours in water temps of 60 or less without a wetsuit. There is training and adaptation (brown fat) that needs to happen for you to be successful. That's part of where the ruffled feathers are coming from with athletes who want to wear wetsuits.
I hope this helps and if you have any questions, please let me know.
Tim
http://www.magnoliamasters.com http://www.snappingtortuga.com http://www.swimeasyspeed.com