> The EUIPO found that the word "open" would be understood by the relevant public as meaning freely accessible, while the combination with "AI" (artificial intelligence) would be interpreted as referring to products based on openly accessible artificial intelligence.
> for certain software and information technology goods and services, the term is purely descriptive and therefore lacks the distinctiveness required for trademark protection
edit: add the latter statement
And to think that this could have all been avoided if they'd just renamed themselves something more appropriate after they decided to focus fully on developing closed models for profit.
More pertinently "the term is purely descriptive and therefore lacks the distinctiveness required for trademark protection." I.e. the problem isn't that OpenAI's products don't match their description, but that trademarking it would unduly prevent others from describing their openly accessible artificial intelligence as "open AI."