I will add my "5 cents". Olympics will not be cancelled, it's too late for that, too much qualification events are happening or already finished, 75% of athletes already qualified and prepare for life time chance to earn the medals. We had also many other sport events which weren't "super-spreader" and the Games also won't be this super-spreader as IOC and WHO are trying made Olympic Village and sport venues the safest places in the world right now.
Japanese people and opposition parties are blaming current government for fourth wave, they have right, because Japan NEVER had proper lockdown as almost every country in the world had in March-April and then in October-January. Such things like banning drinking alcohol outside, closing shops after 21:00 and home office are laughable restrictions. If they would introduced real lockdown way earlier now Japan would have similar number of cases as Australia and New Zealand have. Also having 6k-9k cases per day in country with such huge population is laughable too. They are acting as people would die on the streets and nobody can't get help from nurses and doctors... Most of countries at such number of cases opened everything and are trying return to normal life.
But all those protest doesn't make any sense as it would hurts the athletes the most (they will be for 99% separated from Japanese citizens) and cancelling the Games will not improve current situation and additionaly it would destroy worldwide good opinion of country of Japan, which always was presented as the best prepared country to everything and the most developed, sometimes few years above the rest of the world. The real chance for improving situation is vaccination system which doesn't work in Japan, why? Such smart and well behaved people like Japanese are afraid for vaccines? Hilarious, really. Without those vaccines they will have dozens more waves and will never ends there.