There are plenty of progressive Christians who remember that Jesus’s most important command was to love your neighbor.

The better question is, why are these fundamentalists so successful at co-opting the word “Christian”? Why does “Christian phone network” mean one that blocks homosexual content rather than one that donates 10% of revenue to feed the poor?

Ideally a Christian cell phone network would do both. It would also provide only healthy foods in the office and encourage fitness (gluttony and sloth are sinful), prohibit working on Sundays, and encourage policies to steward our world. It would control off-hours demands for those who are married and have children, and therefore have family obligations to which they must see, and might hold mixers for its singles to encourage family formation. It would expect humility and servant-leadership from its executives and patience from its managers.

I would prefer to do business with such a network but one does not exist. Apparently, people do not believe there's much market demand for any but the first of these.

This is similar to the church itself, which tends increasingly towards alignment with one faction or another. In turn, it becomes blind to the sins of its own and focused wholly on the sins of its schmittian enemy. The conservative church will tell you of the sins of homosexuality but not obesity nor wrath; the liberal will tell you that insufficient love is sinful while ignoring transsexuality. I find neither particularly Christian.

Perhaps the Benedictines could run an MVNO. I am no catholic but they'd probably do a much better job.

Because the more moderate Christians have mostly left, leaving (and attracting) very fringe elements to the churches.

Because the MIT Technology Review would not, upon hearing about a phone network that donates 10% of revenue to feed the poor, contact T-Mobile and request comment on whether such donations from a bandwidth reseller "violate any of its policies". Everyone agrees that you should be allowed to be charitable if you'd like. So there's no polarization pressure in that direction; Christians who want their phone network to be more charitable simply pressure their existing network.

It's not exactly a new thing. People we would describe in the modern day as "religious extremists" or outright authoritarians have been using he name of Christianity in this way for... Well, since Christianity was invented.

Same for Islam and Judaism, though the last one has the roles reversed.

The problem you're trying to identify here is how the public and historic narrative almost completely ignores any positive aspects of these religions and focuses exclusively on the actions of terrible people using religion as cover and justification for terrible acts.

In large part it's relative to location and culture. In the US, if you ask any random person their opinion of Islam, it will be overwhelmingly negative. Vice versa in Islamic societies about Christianity.

There's also a lot to be said of the last era of colonialism wreaking unthinkable damage and actual literal genocides under the name of Christianity, and the damage that Christian "missionaries" still do in the modern day. In recent history, a lot of very, very bad things have been done very loudly in the name of Christianity. Under that banner, Europeans destabilized and destroyed huge swaths of the world. The consequences of which will still be around for generations yet to come. That kind of thing leaks into public and historic sentiment, no matter what. Turns out that the public doesn't really like genocides.

Before I get replies, yes, other people have used other religions to also do terrible conquest and genocide. European Christian colonialism is just the largest and most recent example relevant to Western common knowledge. You should study foreign religions and form your own opinion, it's quite enlightening.

On the other hand, the narrative of the modern era is completely and totally dominated by sensationalism and all the problems that capitalist media bring. Stories about Christian groups donating money don't sell news subscriptions or ad time. Ragebait does, and many religious groups of all flavors are happy to oblige.