By ‘run a promotion’, it sounds like you think she was advertising her book to increase sales.
She wasn’t. She released it online free, in instalments, to entertain children.
She opened a competition to illustrate it (which is why parents were sharing children’s artwork on Twitter), and included some of the children’s drawings in the final published editions.
She is donating the royalties from the published book to charity.
She is an all round good egg (not the finest writer in the world, occasional crass moments, but overall a great storyteller) and does fantastic stuff for children.
Seems a better use of Twitter (and of life) than carping at people online.