Is Karl Marx an authority on the matter? If one famous person in the 1800s says something, is one to take it that they are correct, forever, and that noone can express any view contrary to theirs?

He also wrote literally the opposite to what you put in his mouth, so not only is this an appeal to authority, it's a completely incorrect one. Wonderful.

> It is an undoubted fact that machinery, as such, is not responsible for “setting free” the workman from the means of subsistence [...] in itself it increases the wealth of the producers, but in the hands of capital, makes them paupers

[1]https://www.marxists.org/archive/marx/works/1867-c1/ch15.htm