It doesn't surprise me at all.

Idiomatic Go leans on value types, simple loops and conditionals, gives you just enough tools to avoid unnecessary allocations, doesn't default to passing around pointers for everything, gives you more control over memory layout.

JS runtimes have to do a lot of work in order to spit out efficient code. It also requires more specialized knowledge from programmers to write fast JS.

I think esbuild and hugo are two programs that showcase this pretty well. Esbuild specifically made a splash in the JS world.