Religious Symbols as War Memorials

[Tiberius]

But I'm fairly certain that the crushing majority of US soldiers were always from Christian families of European heritage.

Absolutely 100% irrelevant. The whole point of equality is that the majority aren't treated better than any minority. Even if there was only one non-Christian who died, it is still right to honour them all as soldiers, and not by their religious beliefs. An obelisk is a traditional memorial statue that has no religious overtones.