as many times I have holstered my XD I can't see a shirt binding the trigger, I can see someone trying to holster it and having their finger inside the trigger guard like any other weapon.
You live a privileged life. It's very easy for it to happen if someone's shirt gets untucked and the holster sits at hip level. Standing at a bench, static at the range, I agree, it's not a huge issue, but in a more dynamic environment, it can be a concern...especially for those that have an "expanded" mid-section and a shorter shirt.
I could maybe see a person drawing quickly and not getting a firm grip, but if they don't have a firm grip odds are they won't have a good aim either, going through a class should prevent this improper draw and shoot.
This exactly my point...when you draw it, you may not have a firm grip. Aim isn't the issue, as I'm talking about someone being right up on you. This may not be a "thing" for everyone, I'm just saying that with my hand, I can reproduce the issue some of the time.
Now that I think about it, it may be less of an issue if you're grabbing it from the 4 o'clock, just by sheer mechanics. Maybe that's where the disconnect is. I'm trying it from the 3 o'clock position.