It is not a groan of protest. It's a groan that is saying take a wire brush to my slide bar I have too much brake material accumulation.
After that's done there WILL be some groaning from the bar. It's the way it works. If it's not making some noise, it's not working properly. Friction causes noise in the case of friction sway controls it's part of the design.
Mine got significantly louder when the slide bar accumulated brake material and when they got a little wet.
Business as usual and a small price to pay for a solid towing set up.
Depending on the length of your trailer you may benefit from two.
Do not adjust the tension nut to adjust the noise...only touch the nut if you see a decrease in sway bar effectiveness.
Thanks,
Jeremiah