There is a subtle difference between Kaido and Katakuri, which was the point of this chapter(and Kaido's line).
Katakuri in the same situation stabbed himself as some way to settle the score
But in Kaido's case, he believes "the winner has no excuse", which explains why he didn't mind killing Oden even after knowing he got the drop on him unfairly, and the same situation happening with Luffy now
Katakuri in the same situation stabbed himself as some way to settle the score
But in Kaido's case, he believes "the winner has no excuse", which explains why he didn't mind killing Oden even after knowing he got the drop on him unfairly, and the same situation happening with Luffy now