Why does this entire carton of eggs have 2 yolks each?

Double yolking tends to happen more often in spring and with young or very old birds. As commercial egg producers do not tend to let their birds get old, unless you are getting farm eggs, they are likely young birds.

Automatic candles may be set up to separate these as suspect so they had to be re-run to verify they were not bad, which will result in them being grouped.

When I raised birds, it seemed like brown egg varieties have this occur more often than white eggs, but that is just my experience. Some people actually try to breed for this and it is more common in some birds. It also makes young birds a bit more profitable as the eggs are large than they would normally be for new layers. There are considerable downsides as well for the birds though. The eggs are not viable, almost always if incubated the egg will fail as if both are fertile, the egg cannot support twins, and one failing in the shell will lead to the demise of the other. Also, the eggs are larger, so a young bird is laying eggs larger than it is physically ready to lay, and for an old bird the eggs can become monstrous. This causes a much higher mortality rate in birds.

I have very seldom had double yolks in commercial eggs, but there seems to be something in the water this year. Just last week I had a dozen also that 10 of the 12 were double. Just my luck, I was trying to make angel food cake and did not want them. lol

Eggs are 'candled', visually inspected against a light source to check viability. It seems to be standard practice for double yolked eggs to be grouped together, though I can't find a source as to why that might be. I have heard of it several times anecdotally though.

If your eggs are from a commercial egg company like those common in the US, there are a couple of related factors that could have contributed to your all-double-yolks carton of eggs.¹

First, commercial egg farms tend to raise hens in staggered flocks, with special growing conditions applied to have all the hens in a single flock reach peak productivity and "retirement" age at approximately the same time. This has some advantages of efficiency, but it also means that hens in a given flock will tend to be in double-yolk phases of their lifecycles at the same time.² If the eggs of a single flock are processed together, it increases the odds that individual cartons of eggs will have multiple multi-yolk eggs during these phases.

This is not necessarily a drawback from the point of view of the egg packager. One side effect of double yolks is that the eggs are larger than normal.³ Luckily, there is a market for larger-than-normal eggs. This brings us to the second possible factor: you will tend to find more double-yolk eggs in cartons of extra-large and jumbo-size eggs. Anecdotally, I've found double-yolk eggs in almost every carton of jumbo eggs I've ever bought, and have had cartons with as many as eight-out-of-twelve eggs doubled. Your twelve-out-of-twelve is still impressive, though—and if they were regular-sized eggs, doubly so.

¹ Some brands also actually specifically package and market cartons of double yolkers, but I assume you would have noticed that!
² As mentioned in other answers and comments, hens who are not in the prime of their reproductive lifespan are more prone to ovulation "misfires" such as double-yolk eggs.
³ However, the individual yolks are usually smaller than the yolk from a regular egg. (Similarly, a human woman's abdomen gets bigger with a twin pregnancy than with a singleton pregnancy, even though twins tend to be a bit smaller at birth than the average singleton.)

I love double yolker and I find it is indeed more common at certain times of year. I have one brand that I use and it consistently has double yolks almost year round. Sometimes though I will go a couple months without a single, double, yolker, bummer. I generally end up with an entire carton of doubles when I find one in the batch. I know that there used to be a brand at one store that offered cartons of only double yolks. For some reason, they no longer carry them.