Occupying the same general area in nature is FAR different from snakes being kept together in the same indoor habitat, no matter how well-conceived. In the wild, they're free to come & go, & no doubt the limited amount of air space for captive snakes (with otherwise subtle scents becoming concentrated) might also play a role? There are some snakes that appear to live together in harmony in the wild (such as some rattlesnakes- see videos provided by ASP- or king cobras, per some accounts) but they're the exceptions, not the rule. And those are venomous snakes, not constrictors, so perhaps boids & other snakes are "wired differently"?