The deaths in New York were an appalling tragedy. Innocent civilians suffered and died there last year, and these people obviously need time to mourn. The separate issue of the US government's odiousness (the warmongering, the propaganda) doesn't change this, and vice versa.
The elections of two men seem to have pushed things to breaking point. Ariel Sharon's belligerence has fired up long-term Arab resentment against Israel and the West (leading to a second intifada), and, in some corners, the desire for revenge. Some evil men planned an attack on the US, supported by others calling themselves Muslims - it has raised the stakes rather than improve their cause.
Another election victory, even more marginal than Sharon's, let a man in a leather jacket into the White House. Bush is little more than a stooge to oilmen and warmongers. The war on Afghanistan satisfied both of these factions, as the Americans want to build an oil pipeline through it.
And now, for all the same reasons, war with Iraq is threatened. The US government needs to keep the level of moral outrage pumped up, else they might not have backing to topple Saddam Hussein and install a compliant regime there as well. It is a gross insult to the memory of the people who died to use the events on September 11th like this.
The US needed to show humility and reason after '9-11', but with Bush in charge, this has never been on the cards. Things are going to get worse - hopefully they will get better after that.