The situations aren't comparable. One charge of fuel for a nuclear reactor lasts for years, while natural gas gets burned more or less as fast as it is produce

The situations aren't comparable. One charge of fuel for a nuclear reactor lasts for years, while natural gas gets burned more or less as fast as it is produced (there's some storage, but it's certainly not measured in years). If a bad actor cuts off the supply of uranium for your reactor, you have several years to find a new source. If a bad actor cuts off your supply of natural gas, you'll have a crisis in days or weeks at most.