Before explaining why this has come about, here is the statement from LEGO:
The LEGO Group has adjusted the guidelines for sales of LEGO® bricks in very large quantities.
Previously, when asked to sell very large quantities of LEGO® bricks for projects, the LEGO Group has asked about the thematic purpose of the project. This has been done, as the purpose of the LEGO Group is to inspire children through creative play, not to actively support or endorse specific agendas of individuals or organizations.
However, those guidelines could result in misunderstandings or be perceived as inconsistent, and the LEGO Group has therefore adjusted the guidelines for sales of LEGO bricks in very large quantities.
As of January 1st, the LEGO Group no longer asks for the thematic purpose when selling large quantities of LEGO bricks for projects. Instead, the customers will be asked to make it clear - if they intend to display their LEGO creations in public - that the LEGO Group does not support or endorse the specific projects.
Back in in October 2015, Ai Weiwei requested a bulk order of LEGO, and was refused. Ai Weiwei is a Chinese artist, who wanted to create a work to be displayed in Australia. Previously he has used LEGO as part of broader exhibitions. LEGO refused to fulfill the brick request because it was expected that Weiwei would produce a political work (ironically he intended to produce a piece about free expression).
That wasn’t the end of it, because the media coverage the refusal received led to people around the world setting up LEGO collection points, where the general public could donate LEGO bricks to allow Al Weiwei to complete his work. “The internet is like a modern church. You go and complain to a priest and everybody in the community can share your problems,” he told the press. Meanwhile, LEGO clarified that they were not interested in censoring anyone, but didn't want to give the impression of endorsement through a bulk order.
When the exhibition (Andy Warhol–Ai Weiwei) opened at the National Gallery of Victoria in Melbourne, it turned out that the artist had used easily accessible Chinese knock-off bricks to produce his work. The exhibit used the bricks to produce portraits of various famous and historical figures, with brick built quotes relating to freedom and human rights in front of them. There is more to the exhibit than what Weiwei called the Letgo Room, which will remain in the National Gallery when the rest of the exhibition tours galleries around the world.
The public outcry in response to the decision made by LEGO highlights just how much more scrutiny the company is now under, since becoming the world's largest toy manufacturer. Everything the LEGO Group does is now under the glare of the media and Twittersphere. By choosing to not ask questions going forward, allowing creatives to bulk order bricks and express themselves, it seems LEGO are acknowledging that it is not easy to pick and choose who to support.