I don't know that that's necessarily true. The most recent StackOverflow survey[1] shows a difference of 8%, which is not an overwhelming majority. Granted, that's not an unbiased sample size, but I think the OP above is correct...more data scientists use Python than Java.
So anyone wanting to use this library would have to think about tradeoffs: Are the efficiencies lost in data scientists learning to use Java for modeling worth the efficiencies gained in putting a model in production? For some, the answer may be yes, for some no.