Noone believes that people have full freedom with no context, no extenuating circumstances. What makes arguments like this seem convincing is how uncommon it is for people to think dialectically.

Here’s a very good essay that steps through all of the different parts of the problem, and looks at different views historically. https://www.marxists.org/archive/plekhanov/1898/xx/individual.html

To the hard deterministic explanation that “something always came before,” it asks “what is the role of the individual in history?”

This excerpt isn’t a substitute for reading the whole essay but it makes a point pretty concisely:

But let us return to our subject. A great man is great not because his personal qualities give individual features to great historical events, but because he possesses qualities which make him most capable of serving the great social needs of his time, needs which arose as a result of general and particular causes. Carlyle, in his well-known book on heroes and hero-worship, calls great men beginners. This is a very apt description. A great man is precisely a beginner because he sees further than others, and desires things more strongly than others. He solves the scientific problems brought up by the preceding process of intellectual development of society; he points to the new social needs created by the preceding development of social relationships; he takes the initiative in satisfying these needs. He is a hero. But he is not a hero in the sense that he can stop, or change, the natural course of things, but in the sense that his activities are the conscious and free expression of this inevitable and unconscious course. Herein lies all his significance; herein lies his whole power. But this significance is colossal, and the power is terrible.