This is a common concern, but most folks find that they do just fine, because you normally look over the irons when using the optic.  Yes, the front sight is somewhat in the way, but it doesn't matter because you use the sight with both eyes open, and your left eye will pick up the stuff that is blocked to the right eye, and your brain will combine the images, making the front sight "disappear."  In your mind, you'll see the whole panoramic view in front of you with the reticule super-imposed on it.

UNLESS, that is, you have eyesight issues.  Some folks do, and those folks often do need folding sights.  Others simply prefer it that way, which is fine too.

-Troy