Zoro fans, and it isn't even remotely close in this forum (bar some good trolls excluded from both sides). Although in a way Oda could be blamed for the mess.
What I've seen in this forum is a few handful Sanjibois or Sanji prefering people, are retaliating either in insecurities of being overshadowed by what they perceive as "rival" character or to consistent trolls of Zorobois.
Zorobois or people who prefer Zoro over Sanji on other hand are massive majority in comparison, and are leagues apart louder and vocal in their criticism of Sanji and worship of Zoro, both in quality and quantity. That's just my observation.