You have to focus the outgoing light, the laser energy, just as a telescope does inbound light. To hit a small target (say a 1x1km light sail with a 4x4km beam) at interstellar ranges would require laser emitting equipment many kilometers in size repeated across multiple locations.

How large of a telescope is needed to focus the image of a 4km feature on Pluto? Then multiply that by a few orders of magnitude. Then plug in a laser powerful enough to vaporize a small town. Those are the real problems, not the mass of the sail.

For a given distance to the target, there is a minimum required lens size to focus the laser so (most of) it hits the target. The required size is proportional to the target distance.

When the distance to the target is interstellar-scale, the required lens gets pretty big.