Don't understand the point of maintaining the odd capitalization of old texts

Before the 19th century, the English language contained room for some very idiosyncratic notions about capitalization. People just threw them in wherever and whenever they wanted. For instance, here's the first paragraph of Hobbes' Leviathan (as taken from the electronic version of a 1651 version of the book).

Concerning the Thoughts of man, I will consi…