Which committee decides the speakers in a conference: SOC or LOC? Conferences ask for abstracts for those authors wishing to contribute talks or posters. I wonder which conference committee decides on who gets a talk or poster based on the submitted abstracts; is it the Scientific Organising Committee or the Local Organising Committee?
I would expect this to be done by the scientific organizing committee (if there is not a more formal peer review process).  It is a scientific task, after all, and requires some level of scientific judgment of the quality of the submission.

Agree with TheWanderer that the "local organizing committee" is typically responsible for purely logistical issues, and does not make decisions about what is included in the program.