but by your logic, people should be suing the auto MFG's for not making their transmissions self-replenishing with their fluids ... or not including compressed air tanks that fill the tires automatically if/when they get low on air ... etc.
No, but auto manufacturers should be held responsible if they have, for instance, a brake system that will fail if gravel, road grime, etc. gets in it.
The test is "typical use". If a product fails under typical use, in typical conditions, then the manufacturer of the product has a problem.
A trigger that has to be kept surgically clean in order not to fail is not designed for typical use in a hunting rifle.
