This is an incorrect understanding of history. Eliezer Yudkowsky more or less created the rationalist movement, out of which EA emerged, as a way of funding AI safety research. MIRI is older than EA.
Edit: The original version of the comment implies LessWrong is the single precursor to EA, which is wrong. But it is a relevant and influential one.
I have no doubt whatsoever that EA the organization, LessWrong, and MIRI are all instrumental in EA the movement. But my understanding, including from actually reading just about everything Singer's ever written, is that the applied ethical groundwork for EA was laid at least a decade before LessWrong or MIRI arrived on the scene.