In fact, we can see numerous Marine soldiers right behind Akainu. In all the panels, it's not possible to see a single relevant commander in front of Akainu, like Marco or Vista, and we see other commanders focused on eliminating the Marine soldiers. So, it's not that 1 vs. all commanders fight that people blatantly lie about Akainu having done. If they want a 1 vs. all example, the greatest one is the monstrous feat of Kaidou vs. the 9 powerful samurais.