I don't understand why the production of hydrogen (water electrolysis) is locked behind blue science while hydrogen is needed for oil desulfurization process that is needed to create the sulfur to feed into the blue science in the first place. am i mod conflicting?

Which mods do you use? In vanilla there should be no problems

i use a lot of mod, but i just tested it with only by itself, only N tech, and i still get blue science requirement for water electrolysis, here is the imgur https://imgur.com/a/XPy2NtC

at line 129 and 142 and 242 of the technologies.lua in prototypes folder, there is {"chemical-science-pack", 1}, maybe this was supposed to be logistic science? because i can't find any other way to produce hydrogen

You are right. Nobody noticed all this time. For a quick fix, you can change it for yourself and I'm gonna work on this and other ToDos