If I had to guess I would say it relates to the opinion of some engineers that formal verification is only possible in relatively simple systems, and even then

If I had to guess I would say it relates to the opinion of some engineers that formal verification is only possible in relatively simple systems, and even then only as a mathematical curiosity. As true or not as that may be, the current 'collective wisdom' is more oriented towards automated testing than formal verification, and anything contrary to the popular view gets some natural resistance.