He will be judged for his actions - becoming a burden to other people by choice
For most people, lending their phone won't even incur marginal costs considering the trend towards flat rates.
If you find yourself being annoyed by such situations, note that these feelings are bound to make you miserable, and are unlikely to have much of an affect on the target of your anger. I've found that it is far easier than I thought to just consciously decide not to get worked up such issues, and that it's remarkably effective at improving mood and social life.
Lending the phone to someone who doesn't want to carry one even knowing they will need it? Not fine. That person has little respect to others if they think they can't be bothered carrying a phone but everyone else should lend theirs when needed.
Not to mention modern phones are very personal. Our entire lives is there.
The OP is claiming the way he uses his tech gives him a cost saving and encouraging people to follow suit, when if everyone did that then he wouldn't be able to do the things he does any more. So it's not a sustainable lifestyle, because it leeches off the idea that most people aren't doing it.
It would be quite annoying if they constantly only had $5 in their wallet and needed their friends to cover for them with a card whenever we went out. I can respect the position they're taking, but you've chosen to interact with the modern world in ways that are unexpected and more difficult in some ways. In return, I expect you to think through those obstacles and solve them yourself.
If you ask me ahead of time if I can pay for something, or use my phone, that's totally reasonable. Just going through life assuming that it's a thing isn't thoughtful or respectful of my personal limits.
I'm sure he would be perfectly fine with her not calling at all, and just speaking with her the next time he sees her, the way 95% of humans on the planet are perfectly capable of doing. But she chooses to not respect his very wise and very reasonable mode of living, and you choose to see that as being his fault somehow.
I live tens of hours away from my parents right now. Calling them is how I get/keep in touch with them. If I decided to get rid of my phone, I'd be sure to come to some sort of other solution that would be acceptable to them and not just cut them off.
The issue is he presumably knows that his parents are like this and want to stay in touch with him. If he can't convince them to use email/skype/whatever else, then that's his issue to manage. He's not entitled to push that off onto his friends just because his parents are unreasonable. Either deal with your parents unreasonable demands by having a basic burner phone, or tell all your friends to just not pick up/blacklist it.
To me, is like if you decided you were worried about the environment and started biking everywhere. I can respect that as a decision, but it doesn't mean it's not imposing on me to always be showing up to things late because you haven't adjusted to how long it takes to bike places.
In addition, we're not talking here about how to specifically deal with one person. I've had plenty of friends with annoying habits, and I have managed to mostly ignore their behavior and just live my life. What we're discussing is the more general case - is it ethical to impose this sort of thing on someone else without their agreement/consent. I can both think that my old roommates should have cleaned the kitchen more as a matter of cleanliness and fairness AND have gotten to the point where it didn't bother me that much that I had to clean for them. My ability to not be bothered by it, and to put my friendship ahead of specific annoyances doesn't excuse behavior that makes doing so harder for their selfish reasons.
"Judging people for their actions" isn't the same as shunning them or wanting them dead. Any sort of anti-social behavior that asks for things from other people is going to trigger some sort of judgement or response. Often it will just be ignoring it or helping the person out, and that's fine, but that's part of the calculus of choosing it. You've decided the social cost of asking for other peoples phones is worth the personal moral/ethical/security gains of not having one yourself. Depending on how you approach it and how much you mitigate the asks of others will determine how people judge you on it.