Did you actually check? Just tried on my phone and it’s not there. But if I turn on airplane mode is still works so May be there’s no need for a setting at all.

I think you misunderstand. They are saying that even if it is there, it's a demented example.

How on earth is "if you have internet connectivity, short press the dictation button, but if you want to do only local dictation, long press it" even remotely intuitive, or logical?