Who else is on the subcommittee? Turns out it's 7 republicans and 4 democrats. While I can believe that the Rs may have dominated the vote, it's about as valid as assuming both sides agreed on the cut, since the quote from Senator Lamar Alexander specifies "We've withdrawn..." meaning it wasn't just his decision.
Really, though, you expect one single person is the only one ever asked to decide anything? Well, you might, but I don't think you should admit to it, if you do. But in case you do, perhaps you should examine this:
"Instead, appropriators will zero out ITER spending until DOE comes up with reliable numbers, said Senator Dianne Feinstein (D-CA), chair of the Subcommittee on Energy and Water Development of the Senate Committee on Appropriations, at a hearing today. "We provide no funding for ITER until the department provides this committee with a baseline cost, schedule, and scope," she said.
Don't ask me why I decided to go to google for this stuff, but I didn't really need to. Even the first link in the submission specifies that it was a Democrat who chairs the subcommittee and who warned almost 3 months ago that the funding was in jeapordy.