Hi mary;
Unserviceable radar is an MEL item to provide dispatchability for the aircraft when it is judged by the captain that it is not required on the route to be flown.
It isn't that the industry "tolerates" it - it leaves the final decision to go or not with the captain, where, of course, it belongs.
It is quite safe to fly without radar providing departure, enroute and arrival weather conditions do not require the use of on-board radar.
If conditions require it I would expect the captain to refuse the flight until it's either working or the aircraft is replaced.