Why are 19th Century texts more difficult? As you’ve seen some of the vocabulary is more difficult. The other reason is because of sentences often contain lots of embedded clauses . This makes sentences more complex to read:
Not only are the men kept, in some cases, for a week without the hand of a medical man coming near their wounds; not only are they left to expire in agony, unheeded and shaken off, though catching desperately at the surgeon whenever he makes his rounds through the fetid ship; but now, when they are placed in the spacious building, where we were led to believe that everything was ready which could ease their pain or facilitate their recovery, it is found that the commonest appliances of a workhouse sick-ward are wanting, and that the men must die through the medical staff of the British army having forgotten that old rags are necessary for the dressing of wounds. If Parliament were sitting, some notice would probably be taken of these facts, which are notorious and have excited much concern; as it is, it rests with the Government to make inquiries into the conduct of those who have so greatly neglected their duty.