It's all they have
Sorry, that is not the case. We have data and well-supported theory on our side.
Here is some of the data:
Fossil: KNM-WT 15000
Site: Nariokotome, West Turkana, Kenya (1)
Discovered By: K. Kimeu, 1984 (1)
Estimated Age of Fossil: 1.6 mya * determined by Stratigraphic, faunal & radiometric data (1, 4)
Species Name: Homo ergaster (1, 7, 8), Homo erectus (3, 4, 7, 10), Homo erectus ergaster (25)
Gender: Male (based on pelvis, browridge) (1, 8, 9)
Cranial Capacity: 880 (909 as adult) cc (1)
Information: Most complete early hominid skeleton (80 bones and skull) (1, 8)
Interpretation: Hairless and dark pigmented body (based on environment, limb proportions) (7, 8, 9). Juvenile (9-12 based on 2nd molar eruption and unfused growth plates) (1, 3, 4, 7, 8). Juvenile (8 years old based on recent studies on tooth development) (27). Incapable of speech (based on narrowing of spinal canal in thoracic region) (1)
Nickname: Turkana Boy (1), Nariokotome Boy
See original source for notes:
Source: http://www.mos.org/evolution/fossils/fossilview.php?fid=38