1.) DJI offers many drones related to infrastructure mapping and maintenance, as well as agricultural tasks. From a national security perspective, it is a non-trivial threat vector for a Chinese company to not only have intimate knowledge of US infrastructure by being their drone supplier, but also by becoming a dependency of US infrastructure. In the event of a war, all of the drones could be grounded or used for nefarious purposes.
2.) When it comes to protectionism, I'm generally against it, but I have different thoughts when it comes to China. They have banned Uber, Google, YouTube, Facebook, Amazon, etc, and just make their own versions of it. Then they have absolutely no respect for international laws when it comes to IP. They don't compete economically according to the same rules as everyone else, and don't deserve to be treated the same way.
3.) I have 2 DJI drones. The fact that there is no mention of compensation in this legislature is absurd. Fortunately, I don't rely on these for my business, but imagine if you were a filmmaker, tree trimmer, real estate agent, etc, who had bought many drones for your business. Not only are you grounding the tools that they've already come to depend on, but there isn't an existing viable alternative on the market for many of these tasks.