Well, I was told there was some sort of official vote with like 60% of the population participating with a 75% against as the outcome. I've no idea how Cozumel citizens "vote" for this or that. I am only passing on what I was told by 2 locals who "voted" and represented that it was a government sanctioned vote and not some social media BS vote.
The ecological activist group
Colectivo Ciudadano Isla Cozumel, got together the minimum 3,000 signatures required to request a
consulta popular (non-binding vote, or “citizen consultation”) on whether or not to construct the fourth pier, even though a "no" vote could not stop the project, because all the permits have been granted, the project was approved by the federal government, and the Mexican President wants it built. The activists gave the signed petition to the
Consejo General del Instituto Electoral de Quintana Roo (General Council of the Electoral Institute of Quintana Roo) on March 4, 2022. Six days later, on March 10, 2022, the petition for the
consulta was denied. On April 4, 2022, the Electoral Tribunal of Quintana Roo (Teqroo) ratified the Electoral Institute of Quintana Roo’s decision to deny the request.
I know of no other attempt to have a vote since that one was denied. The Municipio of Cozumel cannot just demand a
consulta popular whenever they want. They are not empowered to do that. The state and the federal government are in charge of that.
There was a non-binding vote on the fourth pier in 2020, but you said in your post that it was held last month, so I figured you weren't talking about one that happened two years ago.