Is there any way to delete a message sent by anyone other than the bot itself, the documentation seems to indicate that it is possible

Your own messages could be deleted without any proper permissions. However to delete other people’s messages, you need the proper permissions to do so.

But I can't find a way to target the message to do so in an on_message event trigger, am I missing something or is it just not possible?
if you're trying to delete the last sent message, e.g if a user is calling a command and you want to remove their message and then send the command.
Use this "await ctx.message.delete()" at the top of your command, it will find the last sent message and delete it.
Deleting User Messages in Discord.py