Uh, Rivet, I for one try to cook my Meat first. Would parasite eggs survive the roasting process??
If it’s cooked to an internal temperature of 165+ °F it should be perfectly safe, so I’d say that roasting it should kill off any internal nasties that are hitching a ride in your squirrel steak, though that might be an interesting function to add to the cooking skill - an additional check to see if you’ve cooked your game meat until it’s foodsafe.
My characters don’t eat raw meat all the time. But it used to be common for me to end up having to do so in the early game when I didn’t have a cooking vessel, back before we could cook on sharpened sticks or make our own strange cookpots made of rocks and string.
Reduced nutrition and enjoyment for uncooked game meat doesn’t really seem like a sufficiently harsh penalty now that cooking it is so much more attainable and the risk of internal parasites would cover that nicely.