Kaido didn't say anything about swordsmanship either yet what you chose to interpret was that he's praising the "DFless swordsman" instead of the king of every conqueror by following the most logical route, which is a) conqueror's haki being a pivotal point in the narrative of this arc (Kaido comes from a crew that wouldn't work because of it, he doesn't want too many conquerors, he addressed it as an ability that only a handful of the strongest will master, his own conqueror's becomes stronger in points of his fight against Luffy); b) Roger being the Pirate King and therefore the conqueror atop conquerors, plus this is what Oden noticed from his clash with Whitebeard (not swordsmanship), plus Roger didn't forge a black blade (unlike those who truly mastered swordsmanship) yet he was the strongest; and c) conqueror's haki being what fits the most with "the key to conquest".
Kaido isn't wanking Zoro anywhere (if anything, the only person he's truly admiring here is Luffy), and Sanji (no need for the "trash daddy son" idiocy, I'm not mentally retarded and I'd like you to not behave as one) indeed lacks the ability to "dominate the world" as long as he isn't a conqueror (and therefore his ceiling is lower than the leagues of Roger).
Also, it's both hilarious and pathetically sad that people like you are either so simple-minded or so enslaved to cognitive dissonance that somehow find it appropiate to link my position to Sanji as if I even mentioned him at all.
"Daddy son" is so much into some of you that it's borderline pathological. I wonder what's so, so, so messed up in your minds that you feel the urge to bully a cartoon character like this. Get some fucking dignity.