I do a pretty fair amount of heat treating using high carbon steels. I can tell you that a fully hardened piece of carbon steel the size you talking about would be much more prone to breakage than a properly hardened and tempered piece would be.
On trigger parts they can be fully hardened to above 60RC and then easily drawn or tempered back to 43-46 RC while leaving the sear face around 55 Rc. Doing this will give the body of the lever the ability to spring and not break in weak areas like where the pin hole is. While the sear face is still appropriately hard to avoid wear.
A good example of this can be found in many of your early revolvers using a flat main spring in the grip area. To hard and the spring will break rather quickly, to soft and it just bends and does not provided the needed resistance. Done properly the spring will last for many many years of use. Still though you can take one that has been properly done and bend it with a pair of plyers past its point of return.
I have no idea if the parts in question have been properly heat treated and tempered or not, but just because they can be bent means absolutley nothing except they are not fully hardened.