1. It's a green laser (it isn't)
2. It's projected onto a white surface, (again, it isn't)
3. 9cm^2 of projected surface area (3cm x 3cm)
Maybe they can modulate the brightness by the amount of stuff present on the projected screen, and maybe even have an outdoor mode, where they use light fonts, that are displayed on a higher brightness, so the overall energy emitted still classifies the device to be class 2. Still, 1mW must be very very limiting here, a 120 nits display is nowhere near usable outdoors, let alone a 120 nits display that reflects the outdoor light just as well as the projector's.
Why on earth they aren't using a green laser if they are limited to class 2 is beyond me though.