Why does ModelSim stop simulation when it encounters an assertion error (e.g., setup/hold failure)?

Description

There is an assertion option in ModelSim that controls the assertion break points (Options -> Simulation -> Assertions).

You can set the assertions to NONE to stop ModelSim from breaking out of the simulation when an assertion is triggered. However, If you make this assertion setting, the ModelSim software ignores assertion statements in your testbench.