A js_binary is normally invoked through a generated bash script (js/private/js_binary.sh.tpl), which works out where node, the fs patches and the entry point are, exports a set of JS_BINARY__* variables, changes into the root of the output tree, and finally execs node. That is a shell process and a few hundred lines of path resolution on every invocation, and it cannot run at all where there is no bash.
The hermetic launcher is an experimental alternative, off by default. To enable it:
bazel build //... --@rules_js//js:use_hermetic_launcher
With the flag on, a js_binary's executable is a small native binary stamped by hermetic_launcher which does nothing but resolve its runfiles and execve node on a generated JavaScript file, <name>_/<name>.cjs.