Because the Pentagon was also attacked on Sept 11. (I know that the Twin Towers are a symbol, but everyone I have read is remembering them. And the people who died on the Pentagon also deserve a remembrance).
Ehsan Jami, the committee’s founder, who rejected Islam after the attack on the twin towers in 2001, has become the most talked-about public figure in the Netherlands. He has been forced into hiding after a series of death threats and a recent attack.