But the "arbitrary" there is too account for the situation where the democratic application of the law wants to inspect the communications of suspected terrorists, and where a judge agrees there is sufficient evidence to grant a warrant.
Unfortunately, that law does nothing against situations like the USA/Russia regime where a ruler dispenses with the rule of law (and democratic legal processes too).
You can't practically have that sort of liberalism, where society just shrugs and chooses not to read terrorists communications, those who wish to use violence make it unworkable.
That is arbitrary interference with all our privacy.