Yes because they are in danger???And again, there are reasons why they wouldn't stay in France, of which you've been given a number of reasons.
If you listen to many of these migrants they say they are wanting a better way of life (which makes them economic migrants)not they are fleeing from persecution because they are not being persecuted anymore in Turkey/Italy/Jordan etc where they landed in a safe country but have travelled through many safe countries to get to France and now want to get to the UK because they are being painted the land of milk and honey by the people that are providing the boats for them to cross to feed their coffers and make money out of them.
France are complicit with letting this happening as they then become our problem and not theirs