2-6 is 2-6. Except when it isn't.
Both the equivalency and its opposite apply to the Nats.
2-6 is 2-6 in that going 2-6 for a week and a half now has the same effect on your record as doing it in May, or July, or Septemeber. On one hand that means you shouldn't worry about it. Last year's team (again under .500 on June 1st), went 2-6 three different times. The 2012 team never went 2-6 but they went 0-5 a couple times and 3-7. It, or something relatively close to it, happens, even for mid 90 win teams.
On the other hand teams that fail to realize these games can't be dismissed are teams that miss out on the playoffs by a game. They blame a single late season bad start or muffed play but should really blame the dozens of "could have been"s over the course of the year. Play hard, try to win every day, solve the problems at hand as soon as you can (like the Cedeno DFA), and don't shrug things off with "it's a long season" because you don't know how the season is going to turn.
2-6 isn't 2-6 in that when analyzing a team during a current season you have to factor in the data at hand. For those other Nats teams there was a lot more data, not just the 2-6, to help us figure out what kind of team we were dealing with. For this team, we only have the 2-6. What the 2-6 tells us is nothing good. The depth and quality of offensive talent is not strong enough that it can suffer through injuries. Sure it looks like Span and Rendon will join Werth sooner rather than later, but this is an injury prone team. The defense, which had a couple question marks, is failing. The bullpen, robbed of two of its better arms (Soriano and Clippard) and two useful ones (Detwiler and Blevins - Detwiler wasn't as bad as you think and Blevins at least had LHB flummoxed, if not a bounce back in him), is a mish mash of maybes with none of the clear hierarchy that can help a young manager out.
But 2-6 is just 8 games so the data size is small. With 50 games under your belt last year, you could have questioned the Nats. They turned out fine. The data says bad things, but the data also says "there's a good chance I don't know what I'm talking about"
One thing that helped the Nats out in 2014 though was the lack of true challenger. On June 1st, they would be only 3.5 behind the Braves, a half game behind the Marlins, a half game ahead of the Mets and only 2.5 ahead of the Phillies. The Nats would go four games over in June. If they went .500 the rest of the year after that, that still would have given them the NL East. The Braves, Phillies, and Marlins would all play well under .500 for the rest of the year. If there are no challengers this year should go roughly the same. If someone rises up things start to look worrisome. The good thing is no one really has exploded from the gate but both the Braves and Mets are set up that they could over the next two weeks. You may not believe in the Braves but that's a good staff and the Mets were a possibility to start the year.
This season has stunk so far, but it's also not even 5% over. The next week or two will be telling on if you have to turn this "what the hell is wrong" into actual concern or if it's just a fluke of timing in the expected march to a title.