A self-sustaining nuclear reaction is a prerequisite for a fission weapon. (that's what allows the exponential doubling of fission events to occur)
A nuclear reactor was also required for the production of Pu-239, which is what 2 of the first 3 bombs were made from.
You are moving goalposts. You mentioned in the first place "fission weapons" and now you take a quote about "nuclear fission reactor" which is a whole different thing.