God, the All-Mighty, created each of us out of nothing. Moreover, He created us human, when He could have created us as something else or not at all. If you observe and investigate your surroundings, you can see many creations that are different from you. Whether they are inferior or superior to you is a matter of your own judgment.
Another aspect is the Providence of God. God may deprive individuals of something they value in order to grant them a manifold return in the Hereafter. In this way, God makes people feel their need, powerlessness, and poverty. This causes them to turn to Him with a greater sincerity and a fuller heart, thereby becoming worthier of His Blessing and Favor. Thus your apparent loss is really a gain. This is comparable to martyrdom, which God rewards with Paradise. Martyrs attain such a rank on the Day of Judgment that even the most righteous and sincere long for it and wish that they had been martyred. What such people receive in eternity is infinitely greater and more valuable than what they lose here.
Although some disadvantaged or disabled people may blame God for their disabilities, and thereby stray from or abandon their faith, many more are strengthened in their faith. It is completely mistaken to use an exaggerated—indeed false—sympathy with the disabled as a pretext for unbelief. It is far better—even essential—that an ardent yearning for eternal life be aroused in such people, for then they can become worthy of an immense reward in the Hereafter.
If the disabilities of some lead others who enjoy good health to recognize that they have much to be thankful for and to improve themselves, their humanity, and their closeness to God, the Wisdom in Divine Providence is confirmed and, to the degree possible, understood.