Sure, but this isn't even a proposed bill. And it doesn't seem to have any chance whatsoever of becoming one.
Sure, if a legislator picks it up and tries to make a bill out of it, and if it gets to the point of a committee somewhere, it will be worth fighting against on principle, but this petition thing seems to have no stance from which to project a real world effect.
(Now, I haven't shot a black humanoid silhouette target in at least a decade, but I'd still fight for everyone's right to do so if it was ever challenged. Of course, the biggest fight would be a 1st Amendment one -- printing and using a product like this is a matter of free speech -- but I'd still be willing to fight for it.)
Am I willing to declare my own standing to fight against local policies or rules about what individual police departments' instructors are told to use for training materials? Ehh...I'm not sure how my dog's in that fight.
It would seem a bit akin to me trying to fight the requirement for IPSC to use "amoeba" targets instead of the standard silhouette in Europe. I don't shoot IPSC, and those rules don't apply to competitions here in the US, so how exactly I can oppose that rule except in the most broad terms, I don't know.