I agree with it as well, 100%. However, in many countries protection against unauthorized endorsement is (automatically) provided by trademark law, not copyright law, making the clause a legal “no op”. That’s why the 3-clause license was simplified to a 2-clause license, based on my research. In other words, if you’re aiming for clarity and simplicity in a legal document that pertains to copyright law, why include terms that don’t readily apply to that body of law?
Regarding the 4-clause variant, I would like to suggest that it not be used. The OSI has not approved it as an open source license (the OSI states that fact on their website), the FSF states that it is incompatible with the GPL, and the various BSD OS projects moved away from it 15+ years ago. I realize you may feel differently, and that you have some concerns regarding the open source movement, but if the goal of the Shen pledge drive was, in some sense, to allow Shen to swim more freely with other open source projects, then I would be disappointed to see it adopt an anachronistic variant of the BSD license. You may not be considering the 4-clause variant, in which case please kindly disregard this paragraph.
If one is looking to cover a lot of legal bases, another option would be to consider the Apache License 2.0. In 2012, the Rust Language project (by Mozilla) switched to non-copyleft dual-licensing under the Apache 2.0 and MIT licenses. The MIT license is nearly identical with the 2-clause BSD license, and they could just as well have dual-licensed with the latter rather than the former. The rationale for choosing Apache 2.0 is that it covers a lot of legal bases, including patent grants. The reason for not going exclusively with Apache 2.0 is that it is incompatible with GPLv2 (but not v3). By giving users the option to use it and/or license derivatives under either the Apache 2.0 or MIT licenses, they’ve achieved very wide license-compatibility with downstream projects. On the other hand, code contributed to the project is required to be under the same dual-license, and therefore subject to the protections regarding patents, etc. Note that Apache 2.0 doesn’t contain clauses related to endorsement or promotion, but does include a clause (#6) stating that the license does not grant any permissions with respect to trademarks (and related) of the licensor.
Best regards,
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Michael Bradley, Jr.
@michaelsbradley