I don't want to learn about Gradle or Maven to understand how a package is working, I'd rather do it in code.
Consider even the current "Hello, world" example in Java (Yes, I know about the proposal about simplifying it), it is tedious, why would I need to understand public/private and classes before launching a simple program?
I fully agree it is a terrific piece of software, especially for industry-grade applications, yet it just isn't attractive.
Main thing IMO, is that you can start out writing pretty good Go code after 24 hours and just improve on your skills as a general programmer. With Java, after a few months you would still need to know about some methods or OOP tips/tricks, design patterns etc. to become proficient.