People have covered the "how" of the split, but not the ideological difference. Metaphorically speaking:

KiA1 wanted to address the fact someone had a fever and put cold water on it.

KiA2 wanted to address WHY they had a fever and treat the underlying illness.

KIA1 said "fever's gone, job's done, oh look, another fever to put water on" while the illness ravaged countless others. KiA2 looked at it and went "job's not done, if you cure the disease you never need to treat the fever again." KiA1 took offense to that, because taking the effort to find the source, and point it out, meant less time putting water on heads and smugly declaring themselves saviors.

Metaphorically speaking:

KiA1 wanted to address the fact someone had a fever and put cold water on it.

KiA2 wanted to address WHY they had a fever and treat the underlying illness.

KIA1 said "fever's gone, job's done, oh look, another fever to put water on" while the illness ravaged countless others. KiA2 looked at it and went "job's not done, if you cure the disease you never need to treat the fever again." KiA1 took offense to that, because taking the effort to find the source, and point it out, meant less time putting water on heads and smugly declaring themselves saviors.