Here is my take. God knew these people were going to be amputated. He knew they were going to lose a limb. If he didn't want them to he wouldn't have allowed them to lose a limb in the first place.
You are quite right,
see, the Bible is clear about God - Exodus 4:11 And the LORD said unto him, Who hath made man's mouth? or who maketh the dumb, or deaf, or the seeing, or the blind? have not I the LORD?
Why should God heal amputees anyway? Is there some reason he should?
Well, yes, there is. If all is possible with god, why draw a line?
I really do not see why God/Jesus cured the blind: God hates both the lame and the blind:
2Sa:5:8: And David said on that day, Whosoever getteth up to the gutter, and smiteth the Jebusites, and the lame and the blind
, that are hated of David's soul, he shall be chief and captain. Wherefore they said, The blind and the lame shall not come into the house.
So why cure the blind and not the lame?
A thing that always bothered me is, "Why didn't God/Jesus ever bother with teeth? Did everyone have a good dentist?"
And why didn't he simply give us glasses? What about the shortsighted? Did he not care for them? And what happened to those with smallpox?
And come to that, why did God make cripples? Why did he make viruses? Why did he give us teeth that go bad?
He's a bit of a useless god if you ask me, have you tried any other gods?