Is it harder for a Sanji fan to admit that Zoro is stronger than Sanji or for a Zoro fan to admit that Zoro and Sanji are relatively close in strength?
Besides, the manga itself does not lend credibility toward the argument that Zoro and Cook are close in strength.
Because if anybody believes they are close in strength, then s/he has to build a convincing case that Cook can bypass Kaido's scales while simultaneously overpowering his tornado attack...or blocking Hakai and surviving....or overpowering Hybrid Kaido and scarring him after having 30 bones shattered.
If such case cannot be built convincingly, then any support towards it is useless.