Note the word “may” in the first sentence. As someone familiar with the canons of statutory construction, I can say that the word may means has discretion to or is permitted to. In other words, you can choose to turn right on red, but you are not required to do so. You may choose to wait until the light turns green.75 Pa.C.S. § 3112(a)(3)(ii)
(ii) Unless signing is in place prohibiting a turn, vehicular traffic facing a steady red signal may enter the intersection to turn right, or to turn left from a one-way highway onto a one-way highway after stopping as required by subparagraph (i). Such vehicular traffic shall yield the right-of-way to pedestrians lawfully within an adjacent crosswalk and to other traffic lawfully using the intersection.
There are a few intersections where I don’t like to turn right on red. Some of them have poor visibility, and I prefer to wait until green. Yet I often get someone behind me honking their horn and basically demanding that I turn. Well, buddy, screw you; I don’t have to if I don’t want to. And if anyone does honk at me, my policy is always waiting until the light turns green.