So how are clamshell packages actually meant to be opened without risking serious injury?
A pair of scissors.
Some of that packaging has a pre-scored section, perhaps on the back, that opens fairly easily.
Sharp clams.
Even with scissors you’re risking injury because you’re creating extremely sharp points and edges that can hurt you if your hands slip.
I use a utility knife, always cut away and watch where you put fingers. ( Usually next to me so the blood doesn’t get on my pants. 
)
Cut slowly and lightly, let the sharpness do the work.
Some companies offer alternatives. Amazon, for instance, offers some items in “frustration-free packaging”.
So was that the actual intent when the packaging was created, to make something that must be opened with a specific work tool on a cut-resistant surface? If you’re in your car, having just bought a new something, with no tools, you’re just s.o.l.?
I’m sure that the people in the shop would be happy to open it for you.
What if the scissors come in a clamshell package?
Explosives.
Isn’t that the exact opposite of why clamshell exists?
I thought clamshells were intentionally designed to be very difficult to open, to prevent shoplifting.
In my experience it still takes a long time and a lot of effort to get the item out of the package once you’ve gotten the perforated part open. It just gives you a place to slip the scissors in.
I’ve used scissors, box cutter, knives and if that fails, I set the package on fire and return it to the manufacturer while it’s still burning.
When I worked the ER of our hospital, every once in a while we saw a serious cut from packaging such as you describe. Can’t the manufacturers of these things be sued? How about class action? ever heard of one or even an effort to file one?
Q
Once you manage to create a starting place with a knife or scissors, it’s fairly common for the hard plastic to tear, creating jagged edges that can inflict serious injury.
There’s no doubt in my mind that the packaging was designed with evil intent.
Here ya go -
You want this one.
It’s not afraid to show it comes in the plastic packaging it’s designed to open.
Today I bought a pair of scissors from my favorite brand, 3 claveles (no, I don’t own stock - but if ever have a chance to buy some, I will). At first sight the packaging was a clamshell. At second sight, the bottom had an envelope opening: just press a bit on the sides and you could slip the tab out and get your scissors without breaking anything 
Combine that with these Cut Proof Gloves and Bob’s your uncle. I originally got a pair of these for the kids to use when they first started to help me cook by dicing vegetables and stuff like that, and discovered they were useful for all sorts of things like opening packages.