Thanks for your interest in our dictionaries. This entry was recently revised to make the Spanish usage clearer. However, I will transfer your report to the team that manages the English base dictionary so they consider adding an example sentence or sense in which they refers to objects (I think more people have asked about this.)
Thank you for your message. As specified in the definition of our first sense of 'they', it is the plural form of 'it', as well as of 'he' or 'she'. I've added an example sentence of 'I love red and green; they are my favourite colours', which should allow our translation teams to show how it works when objects are the subject of the sentence. The new sentence will go to our translation teams for review. Once that's been done, it will appear in the dictionaries the next time they are updated.