There is nothing sacred about the 9/11 terrorist attacks. Many events in history have had more casualties, been more tragic, etc. There is no need to self-censor 9/11 related content.
The victims of 9/11 were basically all innocent and did nothing to the people that killed them. Also a good percentage of the victims died because they were trying to save others' lives.
The other tragedies that are worse then 9/11 are also not commercialized nor should they be just like 9/11 should not be