GoPro camera mounts are very rugged designed for extreme sports use amongst other things. GoPro cameras mounted on drones tend to use lightweight open frame fastenings to save weight.
The majority of drones use lightweight materials filled with expanded foam to provide rigidity where necessary.
Battery packs are not the hard metal cased variety you stick in a torch but multiple layers of plastic type materials wound into layers.
Neodymium magnets shatter into small pieces when exposed to severe shock. Motor cases are formed from relatively soft metals. Larger aircraft are preceded by a pressure shock wave that will probably break up smaller drones and spread the resulting debris over a fairly large area, if any of the debris actually manages to hit the aircraft.
A typical consumer grade drone being ingested and passing through the core of a jet engine is about as likely to cause damage as a duck of similar size and weight. So the risk is not negligible, but neither is it so high as to be a major cause of panic and poorly introduced legislation and restrictions.
Larger commercial drones fitted with high quality stabilised gimbals and expensive camera systems should only be flown and in the hands of professional operators who know the law and restrictions on flight. Anything weighing upwards of 5 Kg represents a severe hazard to any aircraft and also to people and property on the ground if things go wrong. There is certainly a case to be made for licensing and professional training of this category of UAVs.
The cheap sub £50 toys for kids are not the problem, the issue is with the £1500 upwards machines. These devices are not being flown by kids, they are being used by adults seeking an edgy video to post on YouTube without any consideration of the risks to others. These idiots need to be tracked down and dealt with using existing laws. A five year jail sentence ought to be an adequate deterrent if enforced properly.