I also must point out the difference in theory and the practise of any ideology: I believe this applies to any religion or any other faith-based belief. The practise is rarely compatible with the theory.
Absolutely correct, and Islam has more theory/practice differences than Judaism or Christianity.
This is largely because the majority of the Islamic world is still in a medieval condition. So, like the Catholicism during the medieval period, much of the population is poorly educated, which leaves only the clerics to explain scripture to the people; and many of the clerics, like the medieval priests, are not dependable.
Thus, you have a blurring between medieval custom and Islamic practice. This is a problem that requires generations to mend, as it did in the West for Christianity.
Much of the dysfunction is Islam can be explained by simply saying “go look at Christianity when it was 1400–1500 years old”; lots of the parallel problems in that comparison.
I don’t know what the child support issue is that you’ve seen, but Islam is unfortunately extremely vague on the child support issue. Sharia basically says “man pays for the basics for the child”, without defining “basics”. So, lazy selfish men want to interpret that as “subsistence food/clothing/shelter” only. Western child support is of course more reasonable.