Baloney. The site says:
As it turns out, Haeckel's contemporaries had spotted the fraud during his lifetime, and got him to admit it. However, his drawings nonetheless became the source material for diagrams of comparative embryology in nearly every biology textbook, including ours!
Not only that, but according to this news story, it took a 2003 court case here in Texas to remove drawings based on Haeckel's drawings from 2 textbooks and to remove from one book the claim that animal embryos have gill slits. It's worth noting that a group promoting the teaching of evolution in schools agreed with the creationist group on these items. Are you proud that it's creationists who are having to correct textbooks?
And, despite what creationists claim, Darwin NEVER used Haeckel's drawings, nor his arguments, to bolster evolution.
Really? Perhaps one reason for that was that "Origin of the Species" was published in 1859 and Haeckel's theories weren't published until 1866 and his his drawings weren't published until 1874.
Those who came after Darwin used both Haeckel's drawings and his arguments. The drawings in the book I linked to were based on Haeckel's drawings, for goodness' sake!
It was Haeckel who was a big promoter of Darwin, not the other way around. Check your history.