Mate, it is you who claim that God crippled us to test us or whatever. And you cant answer why God would discriminate poor crippled individuals. The guy gets his testicles smashed and he cant even find solace in the church.
If there is no answer that's fine, but humbly I tell you, that you are circumventing.
That's fine.
You say my God cripples us to test us. Let me tell you plainly, the answer is no. God does not cripple us.
Any good that befalls you is due to God, and any evil that befalls you is due to yourself. We have sent you as a messenger to the people and God is enough as a witness. - Quran 4:79
They say 1 out of 30 babies born in this world has a birth defect. In the U.S its 1 out of 33. During a woman's pregnancy, taking folic acid and getting enough iodine in the food can help prevent some types of birth defects. But it's also important to realize that most babies born with birth defects are born to two healthy parents with no obvious health problems or risk factors. In most cases, doctors don't know what caused a baby's birth defect. When the cause is known, it might be environmental (such as a baby's exposure to chemicals or viruses while in the womb), a problem with the fetus' genes, or a combination of these things. There are many genetic causes too. Doctors don't know what causes most disabilities, and certainly God doesn't cause it.
But the fact in the Quran is that all are equal in salvation. Just because you are crippled, that does not have any weight in your salvation.
Nevertheless, your question would be "Why does God allow it"? The counter question would be, should God disallow it. This is why I explained about God in a long post. This requires a full exegesis. A whole book. The day I am done, Ill send you a copy.