According to this link here Bell said: "My own first paper on this subject ... starts with a summary of the EPR argument from locality to deterministic hidden variables. But the commentators have almost universally reported that it begins with deterministic hidden variables."
Also "Despite my insistence that the determinism was inferred rather than assumed, you might still suspect somehow that it is a preoccupation with determinism that creates the problem." (Bell 1987, p. 150)
My understanding(keep in mind that I am not a physicist) is that the violation of Bell's inequality shows that you cannot have a theory with local realism that can explain the predictions of quantum mechanics.
My interpretation of realism is that there are some hidden variables and that the properties we are measuring are there independently of whether we measure them or not. However, the violation of the inequality means that you can still have a theory with local non-realism or a theory that is non-local but does not abandon realism (see here for more details). So you can abandon one of the two.
My question is, starting from the assumption of locality, how does Bell infer that there are hidden variables/determinism(as I showed in the quote by Bell above). It seems to me that if local non-realism is a possibility then you cannot infer local realism just from locality as Bell did. How can you say that locality also means predetermined values, since then you are ignoring the other possibility i.e. local non-realism.