Okay, why do you think that insisting on being able to make an emergency phone call is stupid or evil?
(As other people have pointed out, one of the aspects of this story is that nobody's ability to make the call is seriously impaired. They can go outside or use wires, so it's a non-issue anyway. But that's not what we're talking about, so I'm going to answer your question.)
The stupid/evil is in the "insisting" part. Nobody is doing anything to the insister; the insister is making up a NEW thing that is suddenly "owed" to them, a pseudo-right which previously did not exist. If I'm minding my own business and you forcefully impose a new requirement on me, that's simple aggression. Nobody should ever have to tolerate that, and a big part of the purpose of government is to stomp on the people who get caught doing it.
You have the right to try to make a phone call with your equipment, but nobody ever had the right for it to necessarily work. There are so many reasons it might not work, that it will never be something that anyone will ever be able to take for granted. It will never be an entitlement. Your phone's performance will never be someone else's responsibility. We, all together with everything we have, will never have the power to make sure phones always work.
OTOH, the bar owner, sure as fuck, has the right to use metal construction! He also had the right to open a bar 50 years ago when you didn't have a cell phone. He has the right to open a bar 50 miles from the nearest cell tower, or to open a bar in a city which has cell towers fairly nearby but with iffy performance. He has the right to exist even if you forgot to charge your phone or if you left your phone at home. As long as he's not doing anything to you, your phone's problems shouldn't be his problem.
So while on the face of it, the insistance is clearly evil, I try to allow the stupid-out instead, simply because so many people don't think about rights, ethics, power relationships, etc.
Let's make up a tear-jerker (this thread needs more FUN). Your wife, kids, ten very cute puppies, the nicest nun in history and that celebrity that everyone thinks is a cool guy in real life, all have an acute problem which is easily treated. All it takes to help them, is that a magic syllable be uttered over a phone to another person. Alas, if it doesn't get done, they will burn to death, screaming in agony in front of you. You're at the bar with your family and puppies, the nun and the celebrity, when suddenly you get a whiff of smoke. Your wife chuckles, "Uh oh, it's happening again. Better make the call." You smirk, and say "Yes, dear," as you reach for your phone. It's routine.
So you think about stepping outside, but there was a $5 cover charge and there's no re-entry. There's a landline phone behind the bar too, but you don't want to impose on the bartender, as he looks somewhat busy. The reasons don't really matter, but the point is that you hesitate, and ultimately take no effective action. They burn to death: your wife cursing you in her final seconds, the kids and puppies begging you to do something to save them, a look of betrayed trust in their eyes. The nun insincerely forgives you, and the celebrity says "wait until my fans hear how you let me die!"
You live the rest of your life sad and alone, your soul forever wounded, haunted by the terrible memory. Their fat, melting! Their skin, cracking! Their bones, smouldering like charcoal! The horror!
Later, once you figure out that the building contained metal construction, you can call the owner an asshole. I am ok with you doing that. "You should have realized that sometimes customers like to make phone calls! You don't serve food here. What if someone wanted to order a pizza? Or what if someone's family has a rare spontaneous combustion condition huh? ASSHOLE!!" That's your opinion and you're entitled to it. I might even agree with you!
But whose fault is it really, that your wife, kids, puppies, favorite nun and the cool celebrity died screaming on fire while you watched? It's sort of your fault (you should have gone outside, or you should have asked to use the bar's phone) but as I mentioned above, you never could be sure that it would have worked anyway. It was a shitty, risky situation at best. There might not have been good reception outside, the phone lines might have been down, or the person you call to say the magic syllable, might have stepped away from their phone to go to the bathroom. It might have happened the following week, when you would be camping. Don't get me wrong: You should have done better! But they all might have died anyway.
You know whose fault it is? The fucking universe's, that's who. That is totally fucked up, and it sucks that your wife, kids, puppies, favorite nun and the celebrity were always on the virge of spontaneous combustion. I am not kidding. That totally sucks. It's not fair! Spontaneous combustion, good grief! Who is ready for that?! Nobody really is. You thought you could handle it .. such hubris!
And it's not the bar owner's fault. And if you credibly threaten to use government power against him so frivolously, I would hope that you were the one who ended up getting governed, as a deterrent to other future aggressors. On the bright side, I would govern you compassionately, as I know you're bereaved, and stress makes people stupid and cranky. That's so easily confused with evil, or maybe temporary insanity is a "lite" version of evil.