This is because the second you use a drone you are stepping into federal airspace and subject to FAA rules. Not to mention significant liability if you have a crash. The rules are sensical, but if you don’t follow them there are serious penalties possible. $10k+ and up for an offense.
In this litigious world I do not recommend messing around and hoping you don’t get caught.
Pilot Institute has a great course, as well as a YouTube channel with a lot more in the why’s.