Why do some athiests angrily attack the concept of God or gods?

Because if they are correct and all there is, is what we see here, why would they care whether people believed in a god or not? Everyone is going to die anyways, so what's the point of opposing the idea of a god. Furthermore, if they were pestered by someone who was religious, couldn't they just say, "well i respect your opinion, but i'm just not interested." But there are some athiests who seem to be livid about thiest concepts. The same could be said about thiests towards athiesm. All this pointless bickering is exactly what it is... ...pointless.