I fully accept Harris' use of the word "probabilistically" in his definition of the principle. I don't disagree with him on that score at all. The determinism is indeed probabilistic, but as Harris notes, the probability is weighted in favour of the upward flow of cultural influence from the infrastructure compared to the downward flow from the superstructure.
This also ties in with the field of Ecological Psychology, especially in its Gibsonian form:
James J. Gibson, too, stressed the importance of the environment, in particular, the (direct) perception of how the environment of an organism affords various actions to the organism. Thus, an appropriate analysis of the environment was crucial for an explanation of perceptually guided behaviour. He argued that animals and humans stand in a 'systems' or 'ecological' relation to the environment, such that to adequately explain some behaviour it was necessary to study the environment or niche in which the behaviour took place and, especially, the information that 'epistemically connects' the organism to the environment.
It is Gibson's emphasis that the foundation for perception is ambient, ecologically available information as opposed to peripheral or internal sensations that makes Gibson's perspective unique in perceptual science in particular and cognitive science in general. The aphorism: "Ask not what's inside your head, but what your head's inside of" succinctly captures that point. Gibson's theory of perception is information-based rather than sensation-based and to that extent, an analysis of the environment (in terms of affordances), and the concomitant specificational information that the organism detects about such affordances, is central to the ecological approach to perception.
Given that Gibson's tenet was that "perception is based on information, not on sensations", his work and that of his contemporaries today can be seen as crucial for keeping prominent the primary question of what is perceived (i.e., affordances, via information) before questions of mechanism and material implementation are considered. Together with a contemporary emphasis on dynamical systems theory and complexity theory as a necessary methodology for investigating the structure of ecological information, the Gibsonian approach has maintained its relevance and applicability to the larger field of cognitive science.
Given that perception is the origin of most behaviour, this appears to dovetail quite well with Infrastructural Determinism.
It's also worth noting that
Swenson subscribes to this school of thought.