Honestly, I find a number of mild bits even gentler than many rope halters. Rope halters with thin rope or knots on the soft pressure points of their faces can be seriously painful. I used this example before, but I (a barely 5 foot tall girl) can take down a full grown man wit the use of pressure points, and you can ask him, the pressure HURTS. There are a large number of mild bits designed for riding and communicating more clearly than a rope halter anyway.
Look at mullen mouth unbroken snaffles, or french link snaffles, or bumper sweet water curbs, or those soft rubber bits (not talking about happy mouths, talking about the ones made completely out of rubber that's a straight bar and bends in their mouth). Inside the horse's mouth the horse has the ability to move and hold the bit with their tongue and angle their heads in a way to relieve all pressure. With a rope halter they can't relieve excessive pressure or the mild pressure of it simply resting on them, like they can with a bit.
These are those bits I was referring to:
Rope halters also are NOT designed for riding in, when using one like a side pull you are guaranteed to twist it, putting the knots in all the wrong places, even potentially dangerous places. It slides all up and down their face when reins are used. When using one like a bosal with a rope tied to the bottom, the communication is ALL wrong. Don't even get me started on too much pressure with that one!
See how it slides around? It's nearly poking the horse's eye out:
Many bitless options are actually far more dangerous than a mild-medium bit. I've seen more and more broken noses in horses with this new 'bitless' craze. Mechanical hackamores and poorly fitting rope halters are just plain dangerous. Any tool used improperly is dangerous, bitless does not equal nicer.
All this being said, my horses are all taught riding with mild bits, then I put them in Indian hackamore's, that's my bitless preference. I personally put a nose fuzzy on mine, so they solid rope over the nose has some cushion so that it doesn't bother or rub her nose. I also only use the variety that have metal rings for the reins to run through, rather than fabric loops, so release of pressure is immediate.
Indian Hackamore (this one's pretty strong, with such narrow ropes, mine's thicker and again has a nose fuzzy on):
Now I completely agree people need to spend more time with their horses rather than just up-bitting them. But bit's used properly are just fine.
ETA: Wow in the time it took me to write this it went from no responses to 2 pages xD hot topic I think!