Okay but it's not, because they are STILL welcoming to ALL religions and they're not telling you what to believe in.
This is the trouble with religion. Since they're predicated on a belief of mission and saviorship, a neutral or disregard position is interpreted as opposition. This is not the case! Simply using a logo which looks like a demon is not opposition to any religion - because you can still be that religion and use the software.
We see this time and time and time again. Not bending over backwards to one particular religion is not opposition. In the vast, vast majority of religion such a symbol is not seen as offensive. Often times with religion simply acknowledging secularism or other religions is interpreted as offense. This makes religious tolerance virtually impossible, because in order to make any arbitrary religion happy you have to explicitly make all other religions unhappy.
This is why the correct way to tolerate religion is to simply pretend it doesn't exist. Well, if Abrahamic religions do not exist then the logo cannot be offensive.
If you have doubts this is the most correct way to approach religious tolerance I recommend looking into some landmark Supreme Court cases about the establishment clause, particularly in schools. The justices are good at explaining why this is the approach often taken.