I don't think that it was offensive, but it was a little unsportsmanlike and walking a rather fine line.
Having a dig at the country you've just scored against is setting a dodgy precedent.
What would an appropriate reply have been, had England's equaliser stood? I expect anything would have upset people.
To be fair, the English scoring a goal, then locking any vaguely Hispanic members of the US team in a cage on their side of the halfway line, would have turned some heads