Image was autotraced with zero-fill. Which means youv'e got a black shape with a lot of white shapes on top of it.
You'll have to edit the image if you wish to remove parts.
Select all. Pathfinder > Merge.
Delete the white sections... then use the eraser tool or scissors/knife to cut and remove the black remnants.
No telling. The image could have been drawn with pen and paper, scanned, then auto-traced. Those are typically the results you get from auto-tracing a raster image. It's rare for someone to create artwork in that manner.
Of course, the author could have intentionally set the file up this way to make editing less practical. Stock images are iamges, it's rare to provide fully editable, layered, vector files the same way it's rare to see stock sites providing fully layered Photoshop files.