Ah, OK, I see the confusion. You are not denying that the LEGO Group refused Ai Weiwei's bulk order, and are instead suggesting that he should have ordered whatever sets he needed in whatever quantities he needed to get a sufficient amount of parts, or used third-party resellers to source the appropriate parts.
I'm not even denying that Weiwei is correct in saying that LEGO "censored" his work, but that the reasons the LEGO Group have given for doing so are at best quaint (inasmuch as they are trying to be nonpolitical in selling a consumer product in a capitalist manner!) and at worst disingenuous given that China is non-trivially their fastest growing market, and home to their new sites of production. The Chinese media has been very gleeful about LEGO's decision on this matter!
Edit: I feel, however, that it is important to note that the article you linked doesn't seem to support your claim that the LEGO group offered to sell Weiwei the pieces he needed at a non-discounted price. I think what would be significant to this discussion would be finding examples (or the lack thereof) of people who have successfully bought parts in bulk directly from LEGO.
No politics, religion, and realistic modern guns have always been LEGO's policy since the early days.
LEGO doesn't control what people do with the bricks once they have them, but they don't support those things through direct sales or in their sets.
Did a quick search and this is the best I could find.
https://ideas.lego.com/guidelines
Projects related to the topics below do not fit our brand values and will not be approved for publication on LEGO Ideas. We will decide how a project fits these standards.
a. Politics and political symbols, campaigns, or movements
b. Religious references including symbols, buildings, or people
c. Sex, drugs, or smoking
d. Alcohol in any present day situation
e. Swearing
f. Death, killing, blood, terrorism, or torture
g. First-person shooter video games
h. Warfare or war vehicles in any modern or present-day situation, or national war memorials
i. Racism, bullying, or cruelty to real life animals