There are many people within Christianity who use the Bible to justify their economic and political systems. In fact, the Bible is in no way clear on these subjects.
It is not clear on economics. There are statements in the New Testament impugning the love of money; there are statements in the Old Testament in admiration for a number of wealthy or economically shrewd men. We have everything from Joseph, Abraham and Job being regarded righteous to “you cannot serve God and mammon” and “sell what ye have and give alms.” Neither capitalism nor socialism appear to be endorsed unequivocally. We have statements in support of both.
It is also not clear on politics. Israel was never a democracy. For most of the Bible, it was either a monarchy or it was run by alien powers. God did not appear happy with either state of affairs. He only appeared to be happy when Israel was run by judges. When they wanted a king God obliged, but He was not happy about it. There were statements in the Bible in support of slavery. There were statements in the Bible in support of obedience to authority and that any earthly authority comes from God. Neither of these are followed by the contemporary Christians.
On social issues, there are very clear statements by Paul, but neither Paul most people in the Bible followed them. He talked about men being married to women for life; but most people in the Bible did not do that. They either were single or they had any number of wives and concubines.
On moral issues the guidance is more clear; but even here there is room for interpretation. We have everything from supporting all sorts of wars to “blessed are the peacemakers for they will be called sons of God.” There are all sorts of statements against adultery and “fornication,” there are also positive roles played by harlots Rahab and Mary Magdalene. There is everything from “man who looks at a woman with lust has committed adultery in his heart” to “may he who is without sin cast the first stone.” There is everything from “eye for eye tooth for tooth” to “turn the other cheek.” There is everything from fire-and-brimstone to “God is love.” We have statements for war and for peace; for punishment and forgiveness; for tolerance and intolerance. If a 20-page document that is the American Constitution can be interpreted in so many ways, then how much more would the over 1000-page document that is the Bible.
None of this is to impugn the Bible. It is to impugn its wrongful interpretations. As for things such as capitalism and democracy, they are not based on the Bible; they are based on the work of Greek and Enlightenment intellectuals. These things should be justified by this work, not as the will of God. And possibly this would result in more people taking interest in such things and educating themselves on intellectual and philosophical subjects.