I quite agree - but the idea that there's no difference between Marxism and peasant agitation is absurd, and I just grabbed the cheekiest example to the contrary.
There is certainly a difference, although the degree of difference depends on which group of peasant agitators you are talking about. I am no expert on peasant egalitarian movements, but I do know that there is a significant difference between the Levellers and the Diggers (to consider only the 17th century British movements, some of the few I know anything about). The Levellers had a platform rather similar to republican Liberalism (and in fact were a probable inspiration to the framers of the American constitution), while the Diggers were definite proto-Socialists from what I know.