Yes, they have a right, to freedom of religion, to build a mosque for prayer wherever it fits them.
Yes, others will take offense that they are planning to build a mosque so close to the site of the 9/11 disaster.
No, they shouldn’t build it now and by doing so show respect for those to whom it would offend. Show some respect.
No, those who are opposed should not expand the situation to be larger than it is. Show some respect.
Both sides have strong opinions.
What would be an Anglican/Episcopal response? Show dignity to both sides. The historic Episcopal resolution, in my humble opinion, would be to postpone the construction of the mosque. Work at a continuting dialog about Muslim and Christian faith, beliefs, and world views. In a few years most likely many of the opposition’s concerns will have moderated. At a time when feelings are not as strong I think that the mosque could be built, for the right reasons and with much less animosity.