I am also atheist, and just to expand a bit on something you said: "... but some people of another faith could feel offended...".
Plenty of Christians could be offended too, indeed, should be offended.
Matt 6: 5 “And when you pray, do not be like the hypocrites, for they love to pray standing in the synagogues and on the street corners to be seen by others. Truly I tell you, they have received their reward in full"
A direct order from the man himself to not pray in public. So a Christian should stop her, because she is committing a sin ?
And the prayer was led by a woman.
1 Tim 2:12 " I do not permit a woman to teach or to assume authority over a man; she must be quiet."
So a possible compounded sin is happening, a double sin perhaps ?
I post this half in jest of course. It is Ironic though, that the woman leading the prayer might believe she is earning brownie points with him upstairs, but according the Bible, she is doing the exact opposite ?