Because atheism requires just as much belief and commitment as theism.<quoted text>
I often ponder why it's so important to the theists why agnostic must be redefined so it is incompatible with atheism. So why can there not be agnostic atheists?
No middle ground.
Agnostics are not committed to either. They reserve judgment. Atheists already made their judgment.
But I will bet you won't understand that, and will keep on arguing about it.