The examples you cite — PCs, robots, locomotives, printing presses — each caused various clear harms. LLMs will do the same. Waving off these harms as lack of understanding on someone else’s part doesn’t make them go away.
Some of the things you haven’t listed — air conditioning, internal combustion engines, car-centric cities — are busy causing so much harm that our biosphere is showing the strain.
Other things you haven’t listed — government-subsidized sugar production, sedentary lifestyles due to constant PC use — are busy causing so much harm to out bodies that humans are dying of simultaneous over-indulgence and despair.
People warning about these harms were _right_, and in each case they were greeted by similar dismissiveness. No technology guarantees a rosy future. All of it has a cost, some of those costs are very heavy, and some are permanent.