That's because the people making such decisions are not the ones qualified to do so (see the Lisping at JPL article you linked to). Their logic is probably along the lines of "if it's good enough for industry, ..." -- that's not an ellipsis, it is literally as far as the thought probably went.
Source: I worked at NASA for 4 years.
Note well, though, that the coding standards strictly limit the C++ features you can use. It's not done the way your average bunch of C++ code cowboys sling out an application.
F-35 is a similar example (worse because the contractor was probably at fault here: using C++ made the software system go way over budget on a cost-plus contract, and will likely result in larger maintenance contracts down the road. That's a win-win as far as the contractor is concerned...)
http://spectrum.ieee.org/riskfactor/aerospace/aviation/softw...
That is, many of the "safer" languages try to get by with disallowing explosive and dangerous constructs. With some of the more advanced tooling that is available and good discipline, one can still do some amazing things with them.
As far as I'm aware, Fortran and Algol are not widely used. But feel free to correct me.
What exactly do you know about Ada?