Jiang Chen had previously slain Fang Tianze with a single strike that to others seemed like an outward release of Inner Qi, but only Jiang Chen himself knew that this was not the case.
Not to mention, his cultivation method was substantially different from that of Martial Artists. Martial Artists cultivated Inner Qi, whereas he cultivated Qi and blood. Therefore, the concept of releasing Inner Qi outward was not suitable for him.
The most crucial point was that the blow he had just delivered was made possible by borrowing some of the unique features of the Blood Saber. After all, his cultivation method differed from that of Martial Artists.
As for what Xuan Long and the others had said, that releasing Inner Qi was the hallmark of a true Innate Grandmaster, Jiang Chen felt that he might not have reached that level yet, but he wasn't far off. With one more breakthrough, he would be able to achieve it.