

Corporations drill it deep into your head that you do not positively promote your own products or negatively review competitor products without both making it clear that you (1) work for $Corp; and (2) are sharing your own, personal opinion.
Giving the benefit of the doubt to Plex, they suck at training employees about social media policies.
Might be. It is definitely a thing, though.
When I used to work for a large American corporation that sold products to consumers, they took it extremely seriously and breaking it would result in disciplinary action. It probably had something to do with advertisement laws, but it also easily could have just been because it makes the company look very bad.
That sounds unethical, to say the least. Did they verify if you actually did it, or just “suggest” you do?