In general I think you have a point, but beware of generalising too much - there are circumstances e.g. air gapped security sensitive systems, in which the propositions don't hold in a formal sense, but constraints e.g. security certification, on the installation of external, particularly public, code have the direct effect of causing them [the propositions] to appear to hold.
Been there, seen it, eaten the T-shirt ... and bloody frustrating, but educational (because you are forced to re-invent the wheel in the interests of expediency), it is.
A user level that continues to overstate my experience :-))