Wikipedia lists the cutoff for ancient at 500AD so I don’t think this comes down to perception. Insofar as words have meaning, TFA is using “ancient” incorrectly. Then again, language always seems to slouch towards the extremes. If literally dead can mean slightly amused, maybe ancient can mean a couple hundred years old.
That's just the rough point at which historians stop referring to things as "ancient history", it's not some kind of definition for the word "ancient". Ancient just means really really old. You need to use the context to know exactly how old.
For example if I said "your dad is ancient" I obviously don't mean he was born before 500AD.
That said I think "ancient ruins" is so commonly used to refer to ruins from ancient history (i.e. before 500AD) that it is a pretty odd choice for the headline.