It's not really neutral though, it's specifically from the outset designed to depict something evil in the culture of the religion. The current more abstract logo could just as easily looks like traits of Satan as a random demon. And I don't believe this is an attack on Christianity or Christians, or designed to exclude Christians. I don't imagine it bothers most Christians.
But this is something certain Christians will be put off by, and find unwelcoming, for religious reasons. So hence this is at odds with the code of conduct in my opinion.
And really the whole thread has just confirmed this, I've been just short of accused of being an extremist, and had many complaints about my religion, just for pointing this out.
I think one solution is just not to have codes of conduct, it seems to breed this kind of discussion and vitriol. And apparently there's always favourite religions, ethnicities, etc.; different according to who you ask. And also maybe avoid using religious-themed art in your logo if you want to avoid potential for religious discussion. The people behind the logo probably considered and decided this doesn't matter a long time ago, and personally I respect their decision: but it does mean that it will exclude some people.