We had this here: Is there any pretrained model for emotion detection?
I don't think the problem here is specific to open source authors. In fact I think that is a dangerous starting point: When it comes to free software resources, we will get a split opinion base - engineers that create free software are volunteers creating value for all in the real world, much like site contributors here. In many ways they are heroes that should be celebrated.
The trouble with focusing on the value equation is that it puts the site voters into position of voting based on judging the worthiness of the product. I would fully expect a question placed by a Google employee about pre-trained image classifiers and answered with links to inception networks would get shut down as spam. So what is the difference?
The linked question is the example of what can go wrong with allowing resource request questions on a Stack Exchange site. Most new sites struggle with what to allow when someone has a problem to solve but all they want is a link to something off-site that solves the problem directly. It is very useful to have links to the site subject's introductory material. However, such questions can quickly bring in contributions to the site that have agendas to promote some product or idea. Even when the product is free, the promotion typically has an agenda to increase reputation of the contributor off site - converting Stack Exchange answers into incoming links to the product.
The nature of the question should set the scope for an acceptable answer - if the most appropriate answer is just a list of properties of the project plus a link and disclaimer, then the problem is with the question.
We should start getting stricter about resource requests on AI Stack Exchange:
Vote to close questions that ask for links to completed AI services, software products or projects, in order to just use them (as opposed to understand how they work)
Downvote "Gimme an AI that does X" questions.
I think we can still accept questions about papers on subjects as there is no real history of academic paper writers self-promoting via Stack Exchange. But other resource requests need to be accepted more cautiously.
The OP of the question should look for existing questions about emotion classification in video, and answer accordingly. That would be a valuable contribution. A basic but good question about emotion recognition on AI could be asking whether neural networks are the only high-performing model, or whether NN models represent anything interpretable, whether they can be reversed to generate images that show "archetype" emotional faces, what the loss function should be to discover emotional responses instead of classifying them using supervised learning etc. All those questions would require more than just a link to a project - a brief link (with the disclaimer, but without listing traits unrelated to the question) would be appropriate if the project could be used as an example.
Whether the outgoing link leads to open source, GNU freeware, or a consulting service landing page has nothing to do with what the policy should be concerning placed questions and answers. Items offered with open source licenses and as free services on the Internet just a few years ago are some of the largest multinational corporations in the world. GitHub was not bought by Microsoft for cheap, but what money goes or doesn't go where shouldn't be the main policy driver.
There's nothing wrong with selling products and services (unless you're a Luddite or a follower of Richard Stallman). I don't think there's anything wrong with offering up free downloads that are tied to our own career success if the need for it occurs in the normal flow of SE Q&A.
The case mentioned is not that. It is exploiting the rising popularity of SE to drive web traffic, something that could potentially appeal to ten million other code repository contributors. I'm not sure it matters that much if people use SE to post click bait like this and funnel traffic from Google through SE to GitHub, although the SE staff doing server capacity planning might think it matters.
The main concern for the AI stack is that it waters down the value of the Q&A to a relay for marketers rather than an AI site with a more think-tank feel, which would improve the stack and its member activity.
If somebody puts self-promotion in an answer, it violates the Stackoverflow guidelines, https://stackoverflow.com/help/promotion They have a very strict attitude and flag an answer as spam if somebody has posted a link to his own website/repository. The situation is more complicated, if such a promotion is done in the question, because the asker is always king. Direct flagging as spam is the wrong way. The better idea is some kind or ironic flag with a +100 bounty to motivate the community to search really hard for an answer. But I'm not sure what the official meta.stackexchange position is in such a case, I've found with Google no clear guideline.