Shouldn’t they come to me then and look into my phone instead of constantly looking into my messages on the server?
I think the door is a great analogy.
Right. I believe it’s just laziness on their part. If the crime is abusing children, go catch the guys doing the abuse. If you’re worried someone is in possession of illegal materials go get a warrant and search their home/computer, etc.
There's no such thing as a perfect analogy because the entire point of an analogy is it takes an argument and reframes it in a different context. Different contexts have different edge cases and thus no analogy fits an argument perfectly.
Given this door analogy works for the majority of the arguments being presented (which is impressive in itself given how different the physical and electronic worlds are), I'd say it's actually a pretty good analogy.
Any analogy has its limitations, but I think it is helpful for talking about things like "back doors" (and how that is no different from not having doors at all) or how a proposal is basically only "unintended" consequences and no gain. Feel free to suggest a better analogy.
The main difference where this analogy breaks down is that it is much easier to build practically unbreakable encryption (assuming P != NP), versus practically unbreakable doors or safes.