Others said they had no problem with the plan despite their own lingering pain, pointing to the country's deep belief in religious freedom.
"People are losing perspective," said Peter Griffith of Willingboro, who lost his wife, Donna, 39, an office manager. "We can't deny people their rights. This is a free country. If we say this can't happen, who is next? . . . Everyone is entitled to practice their religion."
The proposal, which has been backed by New York Mayor Michael Bloomberg and gotten partial support from President Obama, calls for a building up to 13 stories high that would house a mosque, a 500-seat auditorium, and a pool. It would be closely modeled on the YMCA and the Jewish Community Center in Manhattan.
The main organizer, Imam Feisal Abdul Rauf, is on a State Department tour of the Middle East, where he is speaking against fanaticism. He is generally considered a moderate Muslim and a bridge-builder, though opponents claim he is a stealth extremist who has supported suicide bombers and other radicals.
It's no surprise the center has sparked unsettling discussions over religious freedom and stoked highly wrought feelings about the terrorist attacks of nine years ago.
According to a recent Time poll, two-thirds of Americans oppose the construction of the center in Lower Manhattan, compared with 26 percent who support it. More than 70 percent agreed that the building would be an insult to the victims of the attacks.
But on Wednesday, a group of 40 civic and religious groups, calling themselves New York Neighbors for American Values, rallied in support of the mosque.
Locally, the 9/11 families who weighed in are also divided, though most are bitterly against it. More than 50 people with roots in the Philadelphia region were among the nearly 3,000 killed on Sept. 11.
"I am a very open person, I really am. But they came here and killed thousands of people, they destroyed many more thousands of lives, they left children without parents. . . . Somebody tell me why this [the center] has to be," said Joyce Rodak of Mantua, whose husband, John, an investment banker, grew up in Bucks County and died in the South Tower.
Virtually everyone said they thought that people in this country have a right to practice their own religion. Many said they would not oppose a mosque in another location.
But not near that site, which they consider a solemn place that must be protected. Peter Shihadeh, who owns a carpet store in Ardmore, said the body of his sister Bonnie Smithwick was never found and could still be in the ground, "in whatever form."
"To me it is hallowed ground, and having a mosque there . . . that hurts," he said. The site is two blocks from the World Trade Center location.
Like some others, Shihadeh said that he believes Islam promotes violence and that the mosque's backers are at least "tangentially" associated with extremists.
"If they were smart, they'd say, 'We're creating a lot of ill will with this; we'll move it a few blocks.' . . . This isn't a question of is it going to be built, but of where it's going to be built," he said.
Susan Jones Bulger of Yardley, who lost her husband, Donald, a 43-year-old bond broker, said she was "devastated" by the plan.
"It's not only insulting, it's almost antagonistic of Muslims to want a mosque so close to ground zero. My girls, their dad's body is there. There's over 100 mosques in the five boroughs of New York, so why put another one so close?"
If the Muslim community wanted to help heal the wounds caused by the attacks, "they would step up and say, 'Why would we want to do this to those families? Why would we want to rub their faces in it?' " said Bulger, who has written letters of opposition to Bloomberg.
Fiona Havlish, whose husband, Donald, 53, died and who has since moved from Bucks County to Boulder, Colo., said she felt Muslims "had an absolute right" to build the mosque, but questioned their motives.
"Are they building it truly, deeply from a soul-level need to practice spirituality, or is it a power play?" she said, noting that the tall building would look down on the site of the attack.
But Griffith said too many people are as intolerant of Muslims as they are of African Americans and people of other races and faiths.
"You can't paint everybody with the same brush," he said. "It's the same as when people look at African Americans or Hispanics and all they see is what they look like and not who they are."
His daughter, Paula Edgar, who was 24 when her mother died, agreed.
"I don't believe Islam murdered my mother. I believe terrorists murdered my mother," said Edgar, an attorney for a nonprofit who lives in Brooklyn, N.Y.
Jackie Lynch, 56, who lives in South Philadelphia with her 31-year-old daughter and whose husband, Terence, was 49 when he died at the Pentagon, said she supported the plan because "I don't want to take any rights away from anybody. A lot of our rights were taken away from us on Sept. 11."
Albert De Martini of Center City, whose brother, Frank, 49, a World Trade Center construction manager, was killed, said he thinks the Islamic center would demonstrate to Muslims "our commitment to religious liberty and open-mindedness instead of the political hysteria of us against them."
The attacks "had nothing to do with Islam. It was a criminal act by a private gang and that we made it a state affair is a monstrosity," said the retired lawyer.
His 91-year-old mother, Alberta, who raised five children in Haddon Heights, said she had thought long and hard about the issue and still was not sure how she felt. But she said she knows what her son Frank would say.
"He was a very, very liberal person, and I kind of think that he would feel that freedom of religion belongs everyplace," she said.
Then she added, "I think the Muslims are getting a raw deal because of the crazy people that did that. It doesn't seem right to blanket a whole group because of the actions of a few."
Contact staff writer
Kathy Boccella at 610-313-8123 or firstname.lastname@example.org.