Gate changes happen all the time, especially when your inbound is late. The implication they did it so you personally wouldn't have to walk as far is... not credible. The person you tweeted to had absolutely zero input in what gate was assigned to your flight.
This happens. You DM via twitter if at risk of missing your connection. IF, you are valuable enough for Delta, the request is passed on to Flight Operations at the connecting airport and they can -
- Either send you a Porsche. Or,
- Try and move your inbound (or outbound - though rare) to gates close enough so that you can make the connection - Delta is serving more then 1 passenger here as there might be other folks trying to make the same connection
Of course, this is not guaranteed but happens.