Too much of this debate fails to distinguish between what's allowed and what's possible
If the police have an appropriate warrant, they are allowed to break down your front door and search your house. However, you are allowed to buy up a second hand nuclear shelter, restore it (including the blast doors) and live in it. Were you to do such a thing (either because you're eccentric or because you have something to hide), a standard issue police battering ram wouldn't have very little impact. So the comparison should not be with search warrants, but on the restrictions on selling really strong doors (of which none exist anywhere in the world as far as I'm aware)
Of course, whatsapp is cheaper, more convenient and practical for more of the population than living in a nuclear bunker, but the distinction still needs to be made.