Bastardeux is right. The source of the cancellation talk is in the slides linked here:
Analysis of the DoD SCMR Options | CSBA
Basically, if you don't touch force structure, readiness or the civilian workforce (slide 4 far right) and try to meet the sequester budget, all new programs cease until such time as more money is available, which it won't be because compensation for active and retired will continue to eat more of the budget.
On the other hand, without big cuts to structure, readiness &c
and to other new programs, you can't produce JSF at the planned level. Indeed, you needed future budget increases to do that, even before sequester.