I don't think that's the case, seems a little too extreme to think that. I believe the central point of someone not directly enrolled with programming as an actual job (or as a hobby taken seriously) picking Fortran over C/C++ has to do with the features it has out-of-the-box, or at least that are more apparent from the surface of language knowledge. Even if it takes one afternoon to implement a certain feature, would scientists WANT or NEED to do that?

Don't get me wrong, this is probably an opinion I would defend if it were exclusively related to programmers being "too lazy to learn a new language", but this is a different learning purpose.