Twitter does this with every URL, Paul Irish did not (as you can see by the fact the link text is the actual URL). It's so that there's more room in the Tweet for the rest of the message.
A very hack-ish way to fix this would be to just force HSTS on t.co and get on the HSTS preload lists in Chrome/Firefox/[..]. That way even though the link would be to t.co, the browser would never make the request to the http domain itself.