"The Rising achieved nothing but thousands of unnecessary Irish deaths."
The death toll was hundreds rather than thousands,the majority civilians many of whom were killed by army fire.
The figures come from Wikipedia link below
Almost 500 people were killed in the Easter Rising. About 54% were civilians, 30% were British military and police, and 16% were Irish rebels. More than 2,600 were wounded. Many of the civilians were killed as a result of the British using artillery and heavy machine guns, or mistaking civilians for rebels. Others were caught in the crossfire in a crowded city. The shelling and the fires it caused left parts of inner city Dublin in ruins.