Yes Zoro is stronger but in the way Mihawk is stronger than Shanks
It's reflected in all of their opponents/parallels. 2200 Doriki vs 2180 Doriki, 1.3B vs 1.2B, Ray and Gaban being said to stand shoulder to shoulder with Roger, etc.
Plus most other rivals in One Piece are near equals. Look at Roger and Garp for example.
You can't say I'm not a Zoro fan just because I listen to what Oda's telling us. If anything that makes me more of a Zoro fan