Why B&W film?
a) Easier to develop at home,
b) Easier to print at home,
c) Consider more 'artistic' and immediately implies you are more serious about photography,
d) Many RF photographers are into 'retro' and B&W film is as retro as it gets,
e) Many uses cameras where they guess exposure - many b&w films allow 2+ stops and can still deliver useful negatives,
f) Many RF/classic camera users have 'heroes' that produced the majority of their work in b&w - so it's understandable that the followers wants to do the same,
g) People likes how b&w images looks - and find colours 'distracting',
h) People like patterns, shadows, human expressions (and prefer b&w film to remove the colour from such scenes and hence just focus on what the subject 'should' be, and,
i) all of the above.