Go, despite using GC, is still a compiled language. From what I've seen (including various test results), Go is usually faster than Java.
There is also the issue of, what is fast enough? A lot of times, people don't really have the speed requirements they say or think they do. To include the code they have written, could be better optimized. It's often better to be more specific about what the requirements are, before making blanket statements about a language not being fast enough. Clearly, many people are fine with how fast Go is.
