Guys have "parts."
Those parts take up space and must reside somewhere.
Unlike women, who, if I'm correct, rarely need to adjust The Girls after the bra has been put on, our parts have a tendency to get jostled out of place all the time. That requires an adjustment of the package.
Without that adjustment, as one Faithful Reader pointed out, we can experience more than a little discomfort; it can downright hurt.
Most of the adjustments need to happen as we take a seat. However, if we do so as we bend, it should pretty much go unnoticed.
I've seen plenty of guys out in public pushing things into a more comfortable position.
Just like everything else that comes along with dealing with our genitals every day, like:
Needing to adjust the goods is a "fact of life" we need to accept, and we should cease being embarrassed by that.