When you google „Taylor Swift easter eggs”, you’ll see that it’s a more specific thing than just „easter egg”, similarly how it has a more specific meaning in software.
Right. Do you think they would still be called easter eggs if Taylor Swift didn't just place hints, but also told people about the hints, exactly how to find them and what they meant?
The article could have said “‘Easter egg’ is a term which means a bit of information or a feature which is left hidden as a surprise for people to find. In the context of Taylor Swift, easter eggs are hidden bits of information which often point at upcoming projects.” That would be overly wordy and unnecessary though because most people already know what Easter eggs are and thus won’t assume it’s claiming that Swifties invented the term.