I don't know how these cheap pointers work but if there is not a driver circuit, I'd also guess it relies on internal battery resistance to make a crude constant-current source.
I've got LED flashlights that use battery-resistance for current regulation.
Lasers don't work properly from a constant-current source (like an LED) but it might be "good enough" for a laser pointer as long as the current is low-enough that it doesn't fry the laser.
Normally laser diodes are powered by a controlled-current source in feedback loop. There are 3 pins on a laser diode, and the 3rd connection is for monitoring light-output for the feedback loop to maintain constant/controlled light output.
I'm no authority on Ohm's law, but if it is already the correct voltage, how do I limit the current. I know motors kill themselves when they don't get enough current. Should I be using PWM to limit what it gets?
PWM won't help... PWM switches full-power on & off (faster than your eye can see or faster than a motor can react). This lowers the average power & current, but you can still fry stuff!
You can't use Ohm's Law directly on the laser because diodes (including LEDs & lasers) are non-linear. That means the resistance changes, drastically, as the voltage changes.
With LEDs, we use Ohm's Law to calculate the required resistor from the voltage drop across the resistor and the current through it. With the LED & resistor in series, the voltage divides between the two components (i.e. 3V across the resistor and 2V across the LED), and the same current flows through both. With the correct resistance, the LED voltage magically "falls into place". (It works because of the negative correlation between the resistance and voltage.)
...Since we know the current-through and the voltage-across the LED, we can calculate the resistance of the LED under these specific conditions. Ohm's Law is a law of nature and it's still true but it's not that useful because the resistance will change if the voltage (or temperature) changes.
You can also calculate the effective internal battery resistance by measuring the no-load voltage, the voltage under load, and the current. (The difference between those two voltages is the voltage dropped across the battery-resistance.)
Of course, there is not a resistor inside the battery but there is a characteristic that makes the voltage drop when current increases, similar to a resistor in series with the battery.