Is there a logical reason why reactions are in low/null space

This has probably been covered many times and if so I do apologise.
I have been playing on and off for a fairly long time. I mainly just do my own thing , have never been interested in PvP but am quite happy to pootle around and make my own, ships weapons etc run the odd mission etc. Since the Trig invasion began I thought I would make a bloackade runner (prowler).
So looked at the industry and as with certain minerals for T1 that have to come from low sec I am happy to pay the premium to somebody else, all the other I’ll mine myself. I run 5 planets. and so try to make what I need from this aspect.
So I purchased all the moon ore, purchased all the correct reaction bps, the helium/hydrogen etc BPs all the component BPS researched them all, (well most the cheaper components I paid for) got it all ready and then went to use the reaction formulas to find that it can only carried out in Low/Null space, what the HELL.
I completely understand certain minerals and other components being restricted to low/null but an actual manufacturing process, madness.
I can not as an individual make T2 tech.
Having to run everything to a POS in 4 space only being then to run the reactions then having to run it all back to where I manufacture for every component.
I am afraid I do not understand the lore , reasoning behind this. The basic minerals etc yes, but a manufacturing process !!!
I have played as a sort of old timey prospector, make my own gear as far as possible the stuff I cant, the raw materials only I will purchase , but I am not after instant need , If it takes me 3 months to manufacture the prowler , that is fine by me, but to run into a brick wall that forces me to head down to low space to carry out the manufacturing process, and what craft would I need to make all these runs carrying material, why a blockade runner, hows that for irony.
As there are only 4 possible sites within 25 jumps and only 2 can run all the different reactions.
I give up. So no T2.