Bultoboy is correct
Going on with the race will change nothing for the people of Japan. They only people that will benefit is Dorna and the race venue. Far too many families are still homeless, living in shelters and are struggling to get working again and are living off meager handouts. The drama is over so the big news is over in the press. A friend of mone has family there and he has limited contact with them. He knows they are alive but has no idea when he'll hear from them again. They couldn't give a damn about the motoGP race. They care more about wether they'll get to eat that day.
The comments on here are mainly pure selfishness of people who simply want to sit in the comfort of their homes, several thousand miles away, and be entertained for a meager hour. The comments are also from the same people who bitch and moan week after week about GP being a boring procession. If you're so bored, quit watching and whining. Then you wouldn't have to care if the race goes on or not either. No matter your reason, you're not the one who health is on the line.
As for radiation, apparently none of you have ever lived near a place that has had a meltdown. When I was 10, Three Mile Island (I lived 100 miles away) had a meltdown on reactor #2. There's a lot to it about the damage inside reactor #2, but evidence got out that contaminated cooling water leaked through the containment area and pressure from hydrogen spikes was vented to the atmosphere. It took 14 years to clean it up. Reports said that everything was at safe levels even the day it happened. The truth that came out a couple years later was that residents got their annual dose of radiation in 1 day, mostly in the form of iodine. It wasn't until 10 years ago that cases of thyroid cancer started cropping up in people who don't have a family history of it. Birth defects are more difficult to nail down. Reports from different sides had different findings. The firm that minitored TMI after the incident had different reports from what those that were monitoring a couple hundred miles away were. Where the inconsistencies came from, I don't know.
The thing is, governments lie. The Japanese government included, if it suits their purposes. They can heavily influence those who prepare the report with the power they wield. They depend on tourist dollars for their economy to thrive. Why wouldn't they lie to keep them flying in and spending their money? In the end, the Japanese as a whole will not benefit from a single MotoGP race proceeding.
You can still be emotionally supportive but not be present. If you think there is more to showing support, they you need to either send lots of your own money or get on a plane and help rebuild with your own 2 hands.
As for the rider's contracts, there's likely nothing in there that says they have to submit themselves to environmental risks beyond their control. If all else fails, they can claim illness that week from lactose intolerance due to a large bowl of ice cream.