'MDPI has a controversial reputation due to past issues with predatory practices, aggressive marketing, and questionable editorial standards, though it has made efforts to improve its practices and is a member of the Committee on Publication Ethics (COPE). While some researchers still view MDPI journals as a viable option for publishing certain types of work, such as negative results or articles needed for tenure, many view it as a publisher with lower quality standards and question the scientific value of its publications, with several scientific bodies in Europe ranking most of its journals poorly.'

Also, what is this claim based on?

"When it appears as if no one has actually looked into worldwide measurements of ocean data?"

Sez who?