So, you're OK with the muzzle pointed under your arm or at the person behind you and muzzling everyone for more than 180 degrees on the draw?
Well, most shoulder holsters point the muzzle straight down alongside of your leg - just like any OWB holster. The Bullet style points it into your armpit, and frankly if I have to choose between armpit and groin, that's a no-brainer for me.
In a horizontal carry shoulder holster you aren't "muzzling" anyone any more than you are when carrying the pistol in a gun rug, or pistol case, or even a long gun in a rack across the rear window of your pickup - because in all those cases your hand isn't on the firearm so you aren't "pointing" it at anything or anyone.
It always amazes me the mental gymnastics AIWB proponents go through to try to convince themselves and others that there is absolutely NO additional risk with AIWB carry. THERE IS. It may be a small risk and one that you are comfortable with, but in an adrenaline dump SHTF situation, you can't explain it away, and unless you've been in a LOT of those kind of encounters you can't say with 100% certainty how well you will react. You can say how you BELIEVE you will react due to your training, but there are no guarantees in life.
There is also a risk of AD/ND when holstering and where the gun is pointed during the process matters. Ask all of the people - including fully trained LEOs - who have experienced "Glock leg" if you don't think so.
No matter what kind of holster you use, there is a very high probability that you are going to muzzle sweep SOMEONE during the draw in a defensive situation. That is a fact simply because you can't control the people or the entire situation around you when things go south to the point that you have to draw your firearm.
Some people acknowledge and are comfortable with the additional risk of AIWB, and that is fine. It may be a very small risk, and you may consider it small enough to be comfortable with it, but trying to explain how AIWB carry doesn't create ANY additional risk seems a little like whistling past the graveyard to me.
Let me ask you this. If someone invented a holster that strapped to your chest and was extremely comfortable, easy to access, and easy to conceal, BUT using it meant that the gun was pointed up under your chin, would you be arguing in favor of it?
No?
Why not?
Maybe because carrying your gun pointed at your head doesn't seem like a good idea?
Well, some of us feel the same way about carrying a gun pointed at our man parts and our femoral artery. If you are OK with carrying like that, fine, but it is pointless to deny that it presents SOME additional risk - or to try convince the rest of us that there is something wrong with us if we choose not to take that risk.