You don't understand why someone would complain about that?
Yes, in that I am of free enough will to choose not to use something or do my homework before making purchases. I'm also not saying that you shouldn't be able to walk around without a smartphone, but choices, like speech, aren't without consequence. If you want to pay for something at a location that only takes cash, but you won't carry cash because it's easily stolen or lost, that doesn't mean they have to accommodate you, it means you're not eating their food. Should they take card? Sure, and you should be able to walk around cashless, but the same choice you get to make, they do as well.
So, for the analogy, let's say lots and lots of businesses and public utilities are cash only, and carrying the cash exploits you for Google's profit somehow. Or we could stick to the idea that carrying cash is a theft risk, but let's say the businesses are indirectly in cahoots with the pickpockets through a chain of corruption and that's why everybody requires you to carry cash and be vulnerable.
You can choose not to do it, and your choice is not without consequences that are morally wrong, and you'd be right to complain about that. Otherwise if "not without consequence" implies that you shouldn't complain, then you're offering a viewpoint of it being a dog-eat-dog world, and that's just the way it is, if you resist you'll suffer and you're a fool, so take the easy path and don't worry about the morality. Resignation.
I realize, however, that having both a phone and a home computer may be a privilege that others may not share. That's the rub. Users with only phones for connectivity are made more vulnerable by an exploitative digital system. In that, the author is correct. It's a terrible ecosystem and it begs legislative intervention but I haven't a clue how that is to be accomplished.
Ultimately I declined to use the app and hid my coat under a chair lol and I will not return to the venue.