Which begs the question. When does a "start" sequence end? Somebody has said it is after turn 1, others have said it is after the first lap. I am trying to look for a written rule regarding this but could not find any. If it is after the first lap, then does it mean that drivers are allowed to aggressively defend more and is allowed to crowd other drivers for position for the entire lap? Because if it is, then we have a loophole that allows drivers to defend aggressively, even if it is just for a single lap of the race whereas if it is after turn 1, then this loophole is closed, at least after they cleared turn 1.
You can bet in the rare cases FIA and stewards are applying common sense, there will be calls to put a stop on it when either theri preferred driver get's the wrong end of the stick or when their disliked drivers apparently get away with stuff.
As of now, the start phase is treated differently, simply because it IS different from other phases of the race by design. Never again in a race will so many cars get bunched up as much as during the first few corners, this naturally leading to more close encounters between the drivers. If the FIA would come down on every marginal encounter during the first lap, we would see maybe 2 to 4 drivers getting a drive-through each race from incidents on the first lap. That's not to say drivers can do as they please, as evident for the PM and RG penalties, but things are generally handled a bit more lenient in the first lap, especially in cases nothing ultimately happened.
As to the actual case, I still believe Di Resta already losing ground to Alonso already before he was on the gras makes this pretty much a non-issue, and completely different to Vettel / Alonso later in the race, where Alonso had a massive speed advantage at the point Vettel cut him off. Or IOW, I don't see how Di Resta would have got by Alonso even if there was 3 metres more of tarmac to his left, he just don't has the speed to drive by anymore.