This is broken to not have the Option of setting the button to be a toggle on/off, or a press-on-release-off.
I can play with toggle on/off, but generally prefer press-on-release-off controls for most things that I will change between quickly. Crouch, sprint, aim, etc.
Why is this superior for me? Because it simply is "While this finger is pressing the key, I am doing X". So, I want to aim? I keep holding down the right mouse button. I'm done aiming? Release the right mouse button.
This doesn't make it harder for me to aim, it doesn't hinder me, this is simply how I video games.
If it is toggle aim, I will generally, out of habit, still hold down the button. When I am done aiming I release the button to indicate that I am done aiming and wish to stop. However, with toggle controls the game doesn't. I continue to aim because I have only toggled the action, and must hit the button again to change the toggle.
A "Bug" is when something unintended happens with a system. For many of us this Is a bug, and it is Is Broken. Yes, it is a design bug/oversight that only effects a portion of the userbase, but that is not a small portion of the userbase, and should be addressed by the developers.
Why should we be forced to 'adapt' when making this an Option is so easy?