Are laws prohibiting marriage for those under 18, permitting consensual fornication, and preventing marriage to foreign women considered man-made laws that contradict God's law, and is the last of these considered blatant disbelief?

There is a significant difference between enacting a law that permits consensual adultery, which is pure evil and a blatant defiance of Islamic rulings, and enacting a law that prohibits marriage below the age of eighteen or prohibits marriage to foreign women. The latter falls under the purview of the ruler's restriction of permissible matters for the sake of a public interest, and it is considered a valid issue for ijtihad (independent juristic reasoning). The Islamic Fiqh Council has determined that the matter of setting the marriage age for young girls is entrusted to the ruler in each country. The ruler has the right to determine the appropriate age for marriage and to stipulate punishment for anyone who marries off a young girl without the judge's permission. Furthermore, health regulations should be established for marrying off young girls.