Amazing lack of understanding of the problems of commercial aviation shown on this thread. Most European flights have a slot time to make - with the consequent risk of a delay measured in hours if it is missed. And, yes, sometimes it needs 30mph.
Quite frankly some of you sound like those who sit in the overtaking lane of motorways secure in the knowledge that you are doing close to the legal limit - so no-one has any right to attempt to overtake you.