Not only Americans if that makes you feel any better. It's the same for every country until the elections are over in July. The ruling party can't risk the votes from the geriatrics who control the country. (basically young people don't vote here, much to the determent of the country and some of our ridiculous policies). They'll happily complain but won't take the time to try to vote out the ruling party. The average person who actually votes doesn't want foreigners back (ever basically), so even though the government knows and acknowledges it's a necessity, they have to pacify the voters with the controlled and confined tour groups for the time being and can't rock the boat now.

I'd expect a fairly open border policy again by August or September, but absolutely no widescale reopening will happen before the election, nor an announcement of one to avoid upsetting the voters. So basically if your flight is before August, then you need to rebook it to transit the same airport. As of now JL alternates days between NRT and HND on a lot of the US flights to give people the ability to connect to cities that only operate from one airport or the other. You may have to check around with schedules, but JL flies to JFK, ORD, BOS, DFW, SFO, LAX, SAN, and SEA, most likely you can get a matching airport for your dates without having to rely on HND to NRT being allowed again.