The major powers are endlessly engaged in hacking operations against each other. This is just normal, and no one needs to "admit" to it for that reality to be true. The notable part of this story isn't that Russia tried to compromise a US system, but instead is that some Russian party (whether official or unofficial) apparently had DOGE credentials moments after they were created, which indicates that DOGE is thoroughly compromised. Which should surprise absolute no-one.
Look at what they did with the 2016 election. They hacked that too and didn't hide anything, but when they were accused by the US government they claimed innocence and blamed Ukraine. The allows Russian people to say "Look how awful those Ukrainians are for hacking America; and look at how awful America is for blaming Russia."
So they hack their enemy, and then use that to reinforce the false narratives they tell their own people. It's gaslighting at the national level. Russia is as if your emotionally abusive partner was your government. America is becoming the same.
