Driving side by side in the pitlane is not reckless, its is taking a risk but F1 is risk averse enough as it is, clashes are met with penalties.
And with pitlane limited speeds and only essential crew in the pitlane not particularly dangerous either, at least not a lot more than normal. There is always a chance that a driver gunning it out of his pit box will lose the back end and hit somebody, whether he is racing someone in the pit lane or not.
Infact if there was anything reckless about the whole affair, it was Vettel pushing Hamilton further to the right, beating the opponent out of the pitlane may well be a necessary move to win a race, whereas deliberately trying to push an opponent off the path and into danger is uneccesary and reckless.
IMO there should be enough room for two lanes in a pitlane, American style, so long as speed limits are obeyed then there will be no stupid arguments and penalties.