I'm curious why you must be able to re-holster using just one hand. I can see a LEO needing to holster his piece while keeping a hand on a suspect, but I see no big disadvantage in two-handed holstering for civilians.
It's a good question. The short answer is the same reasons a cop might need to. However, there's a safety aspect as well.
If you have to use two hands when reholstering it will put your support hand in front of the muzzle. That's bad. Even if you were able to do it without covering your support hand with the muzzle, how do you keep your concealment garment out of the way as you reholster?
I could go on and on, but there's no point. The benefits of being able to reholster one handed far outweigh the downside of two hand reholstering.
It's not my goal to try to change anyone's mind. I'm just trying to offer up a better way to do things based on a lot of combined experience and training from guys who have more experience than I. I understand the value of a comfortable holster. It just makes more sense to me to have a gun that's easily accessible than one that's super comfortable. If I wanted comfortable, I wouldn't carry. Carrying a gun is comforting, not necessarily comfortable.
This is why I'm an advocate of spending more to get a good holster and belt rather than try to save a few dollars. It's been my experience that $25 holsters are neither comfortable nor durable. Just because a belt is leather doesn't mean it's a good one for carry. So, a quality holster with a stiff belt is much more comfortable and therefore, makes a person more likely to carry. AND it will allow easy access to the gun when needed.
Also, any training school worth taking will require you to have a holster that stays open for one hand reholstering. You should seek training if you carry a gun.