I'm not so sure that's true. The current E-Class manual does not specifically warn its emergency brake assist is ineffective against stopped vehicles in, or partially in, the lane. Indeed, it specifically seems to indicate it will brake to reduce collision force.
Our Volvo V60 has radar+lidar for this case, and will apply as much braking force as necessary. It even works with something as small as pedestrians and bicyclists. It's awareness of the road around it is pretty impressive.
Considering the rapid expansion of automated braking systems over the past two years, I'm sure there are more.
Still, ok, let's assume that "virtually" no automakers besides the two mentioned here support this case. Tesla is continually stating how safe the system is, and yet it has major limitations that at least some of their competitors have solved. I think that's what gives some pause. Even if AP wasn't enabled, this is clearly a major limitation of the current sensor suite or software package. It seems clear to me, at least, that an automated emergency braking system should be able to detect a big truck stopped half in its lane.