You expect people to start running at 5-6km/h which is about a fast walking pace? That seems unduly slow?
I’m horribly out of shape and that’s pretty much what I can manage. The question isn’t how fast _should_ I go, but how fast _can_ I go so that I can come back and do it the next day.
If you haven’t ran before and are carrying some extra weight then yeah it’s probably a good place to start for your first couple of short runs. Even running slowly puts additional stress on your achilles so it’s a bit of a wake up call to your body. Running slowly for 10 minutes a few times when you’re just getting started isn’t going to hurt anyone and if everything checks out then you can start to up the pace.