Somebody looked up the dates of the Roman occupation of Britain! Ah, journalists.
If you listen to the interview, it is made very clear why they state that it is a Roman burial. The skeleton is in th e”Roman crouch position,” which is apparently the way that the Romans buried their dead in Britain at the time. There were also pieces of Roman pottery in the grave.
The lead archaeologist, Mark Holmes, is the speaker. He is the lead of a team of archaeologists working on the site. THEY are the people that identified the skeleton as Roman, not the journalists.
The interview is actually quite enlightening. There are other reasons to mock them, but mockery in this case is not applicable.