TCMalloc and Transparent Huge Pages

https://google.github.io/tcmalloc/tuning.html#system-level-optimizations says:

> TCMalloc heavily relies on Transparent Huge Pages (THP)

And requires that `/sys/kernel/mm/transparent_hugepage/enabled` be set to `always`.

This requirement is not ideal because:

1. The default for `/sys/kernel/mm/transparent_hugepage/enabled` is often `madvise`.
2. Some legacy applications exhibit performance degradation with `always` option.

I wonder why wouldn't TCMalloc explicitly request transparent huge pages using `madvise(..., MADV_HUGEPAGE)`, to not have this requirement, please?