光说 = all talk and no action.

it means“just to say sb" , "光” not only means "just " aslo strengthen the tone I know this guy insists on getting to the bottom of the matter for everything, he does not know to save my face. Don‘t just say me ! what about you ? Enn ?

没太明白你的意思

“光说不练假把式，光练不说傻把式，又练又说真把式。” This is originated from a Chinese proverb. This means Talking without practice is fake. Practice without talking is dumb. Practice with talking is real.

in this context it means don't just blame someone else, think of yourself's mistakes