If I wasn't a Christian, I dare say I could have become one of those self-serving, self-seeking, self first, self last, self always kind of people. Thankfully, I'm not
I give to charity, but it's not so I can merely feel good about myself, and I'm happy for my taxes, whether direct or indirect, to fund programmes such as healthcare, education, welfare, etc. Society, in itself, is greater than the sum total of its parts, which is why any notion of the common, or public, good, is far from abstract
Issues, such as child poverty, lack of affordable healthcare, can be very much moral issues as well as abortion, same-sex marriage and stem cell research, for example
As for the Bible sanctioning the tithe (10% to the church), and that alone, as a mandatory tax, well society has evolved and become much more complex than it was back on that era. Of course, in an ideal world no man, woman or child would be dependent on either the government nor on charity for a helping hand. As a Christian, I champion the plight of those less fortunate than myself
Dave