Loss function used in run_mmimdb.py

Hi,
Why BCE was used in

The labels seem not binary to me.
label_frquencies looks like

Counter({'Drama': 8415, 'Comedy': 5107, 'Romance': 3226, 'Thriller': 3110, 'Crime': 2287, 'Action': 2154, 'Adventure': 1609, 'Horror': 1603, 'Mystery': 1231, 'Sci-Fi': 1212, 'Documentary': 1195, 'Fantasy': 1162, 'Family': 975, 'War': 804, 'Biography': 772, 'History': 663, 'Music': 632, 'Animation': 586, 'Musical': 503, 'Western': 423, 'Sport': 379, 'Short': 281, 'Film-Noir': 202})

What may I miss? Thanks.