But it's not forbidden in many other religions and emojis are for everyone.
I don't really care if there's a "God emoji" or not and wish good luck to those who'd have to picture God in an emoji, but this freedom and respect thing goes both ways. A group is free not to like or use this emoji, but they don't get to stop others from liking or using it.
While some monotheistic religions don’t explicitly prohibit it, I’m not sure that any encourage it, or have any particular conception of what God looks like.
Catholicism, some Protestantism: Not prohibited, God doesn’t look like anything.
Islam, other Protestantism: prohibited, God doesn’t look like anything.
Judaism: prohibited, God doesn’t look like anything.
Like, I’m not sure anyone would thank you for this emoji.
Plus Unicode already includes a ton of emoji that Islamic fundamentalists doubtless consider unacceptable. Liberal Muslims can presumably put up with other people using a God emoji just like they can put up with other people using a devil emoji.
Also many variants of Protestantism. And even in monotheistic religions which don’t prohibit it, generally God is not considered to look like anything.