There ought to be a distinction between driving which is dangerous, albeit unwittingly (due to the ridiculous levels of acceptability which the motoring lobby have engendered), and driving in a manner which is also dangerous, but wittingly, ie when you're pissed, on the phone, driving like a lunatic etc etc.
The problem for those on the receiving end of tragedies like this is the use of the language. Death by careless driving as a phrase is both a real ambiguity and a huge insult.
However, there is a multi-stage battle here; first the language needs to be changed, which should help the attitude shift, then the charging needs to be applied more robustly, and then ultimately sentencing needs to reflect what's felt to be fair (and sentencing is so far away from what those who have been impacted by poor driving feel to be fair), and most of all that sentencing should include more frequent use of much longer bans. And even much more frequent use of shorter bans for lower levels of driving misdemeanour.
That's a long road, and the only way it can get started is by a shift in public attitude to poor driving, and all the probably hopeless petitions to lengthen sentences help us along that road, even if individually they don't achieve their immediate and specific goals.