I don't agree with this view that every communication, especially online, does not warrant the highest security parameters at our disposal. Assuming there are alternatives with better privacy and security available, I believe we (or the ones who care about such things) should adopt those and evangelize those among others we know. The default should be to treat communication between different parties as nothing but their own business, and nobody else should be snooping around for any purpose.

Other than the above are concerns of a larger magnitude - most people don't understand the true implications of not having privacy/security until it personally affects them. So I always try to push people to use something that's better (may not necessarily be perfect) privacy-wise. Also, when the lowest common denominator is filled by privacy invading platforms, all of humankind stands to lose because of the way money is made by these platforms and how "easy" or "free" those appear to be in the eyes of the users. In a larger sense, we're probably sabotaging the availability and legality of private/secure/easy-to-use communication platforms for the people it matters most to, like those in a repressed regime, journalists/investigators who go against the current powers, etc.

TL;DR: (Usability concerns aside) We have nothing to lose by treating every communication as warranting the highest privacy and security. But we do have a lot to lose by doing otherwise.