That’s quite the claim.
Yes, it is, and as explained in the video the original author (and also the person explaining it) admit it is quite a claim, then proceed to demonstrate the veracity of the claim. I suggest you grab a cup of jo, settle in, and watch it. It addresses the points you bring up directly.
[EDIT: Re: Quite a Claim: Yes, and thus fitting the OP's "mind-blowing" criteria for the thread :-)]
The very short answer to "are you immoral for purchasing a cell phone" is "probably yes".
The proposition is not an easy one (it accepts it is extreme), but it is hard to deny when you march down the logic.
You've committed reductio ad absurdum.
Yes, most people are probably acting immorally and they are not even aware of it.
That doesn't mean it is a pointless exercise to identify the immoral behavior and strive to reduce or eliminate it, even if it is impossible to completely do so.