Once you commit to Atheism doesn't ruling out a possibility disable you from continuously objectively investigating it?
1. I haven't ruled out a god just because I have not found a reason to believe it exists and have reason for acting as if it doesn't (or they don't).
2. Being human disables you from objectively investigating something.
What positive purpose is there to committing to Atheism?
The same positive purpose to committing to not believing in Santa or the lumineferous aether.
I just do not get it, I prefer to look at things from both sides and keep my options open.
Same here. I don't go around saying there will never be any evidence for the existence of Santa, the tooth fairy, the Garage Dragon or Yahweh or any deity like entity nor do I say there will never be a reason to consider that they do in fact exist.
Right now - I've made the decision to be epistemologically consistent which means if I decide to not believe in the Garage Dragon I should treat all other entities with the same level of support in a similar fashion.
From where I stand I think there's good arguements on both sides that are getting us no where!
I have yet to come across an argument for the existence of a god that is remotely as compelling as say, the argument for the existence of dark matter.