Well, that seems to be an issue that is not unique to him. Some others of the same era were equally inattentive to surrounds. I speculate (my personally owned opinion) that the "sloppiness" was a function of two things: the complexity of photography in those days, and the complexity of orchestrating the allegorical scenes. There was a lot to think about and it is not clear that these images were produced in a manner to be "picture perfect"... meaning publication or award-winning quality. Ohter Victorian photographers were definitely interested in sales. I'm not sure that Carrol/Dodgson was so motivated.
Not to forget Julia Margaret Cameron's concept of focus, which Dodgson criticised.