If you posited an earlier dating of the people of the Americas than the accepted one (Clovis First), mainstream archaeologists were going to destroy your career.

The finding

What the evidence shows

The speaker used the past tense here, so the claim is about the old Clovis First era, not today. Pre-Clovis researchers did face skepticism and ridicule, and one case saw funding dry up for a while. But the careers described were not destroyed, and one archaeologist reviewing the case says they carried on and even advanced. Since the early 2010s the consensus has accepted pre-Clovis people in the Americas, so the present-tense idea that archaeologists risk their jobs this way is out of date. A check that would flip this: documented cases of archaeologists fired or barred from the field for proposing pre-Clovis dates.