The truth is there are two reasonable platforms, as long as that is the case we should apply scrutiny.
Even more comparable is postal rules: at least here, there are very explicit rules about opening someone else's mail, or even destroying it. Even if postal/courier services are businesses, they have to operate within the boundaries a society sets up for them.
And finally, you can take it even further: some "businesses" operate on the fringes of legality and sometimes illegally too (think loan shark operations, casinos, betting markets... but also "protection services" and similar).