Google maps shows 29 min by car and 46 min by transit from HND to Skytree (these are few things I know in Tokyo, 5 hours by foot, btw) so I would not trust something you read on Reddit, much less in a community called literally "fuckcars", seems that it might be exaggerating to support its bias.
Same with Siena (I picked just random points "Hotel Athena" and "Farmacia Ravacciano" as they were highlighted on the maps) 17 mins by car, 26 mins by transit (though walking is faster than transit and biking is faster than car, apparently you cannot drive through the city, very progressive).