The BSD/MIT license only mentions things about redistribution. But I don't see any restrictions on the initial release of a BSD-licensed program. Is it possible that I write a program, but only release its binary under the BSD-3-Clause license? If so, why are BSD/MIT licensed programs considered to be open-source/free?
- Is it possible to release binary-only under a permissively-free licence?
- If so, why are BSD/MIT licensed programs considered to be open-source/free?
They're not, necessarily. Source code that you receive under BSD or MIT is considered to be free software. Binaries would just be considered freeware, because although you're not paying for the binary, you aren't (in any meaningful sense) getting some of the four freedoms.
A binary-only distribution of software is very common for commercial software, but it is also possible to distribute binaries with a permissive license like BSD or MIT.
The advantage of this strategy might be in the ease of distribution and re-distribution. However, it might also be a double-edged sword, because the users don't know what's in it (possible malware, patent claims), so users will be hesitant to use it.
Permissive licenses commonly allow modifications, translations etc, and that includes reverse engineering and de-compiling. Therefore, for experienced programmers, there is a path to the source code related to the binary, unless code obfuscation techniques have been deployed (which again should trigger even more doubts among users).
So should a binary-only distribution be considered 'open-source/free'? Definitely not. It raises a lot of questions.
Open-source licenses are licenses suitable for releasing source code of computer software. Some of such licenses (like GPL) are copyleft, they require you to release the source code of your own software based on open source code, others (like BSD) don't have such requirement.
For instance, most compiler toolchains include some source code. One example is ARM/Cortex core library CMSIS (Cortex Software Interface), which was initially released under a BSD-like license and later switched to Apache. Yet a lot of ARM software is commercial and closed source. All the authors have to do is to mention that their software includes code from ARM Ltd. to fulfill the license terms.