Exodus 12:48 - And when a stranger shall sojourn with thee, and will keep the passover to the LORD, let all his males be circumcised, and then let him come near and keep it; and he shall be as one that is born in the land: for no uncircumcised person shall eat thereof.
Joshua 5:2 - At that time the LORD said unto Joshua, Make thee sharp knives, and circumcise again the children of Israel the second time.
I'll also mention Abraham getting circumcised. Since you're arguing only Jews, or Israel needed to be circumcised, yet, Abraham was neither, and still got circumcised.
This (Joshua 5:2) was referring to Israel. I'll note, Israel at this time was made up of the offspring of both, natural born, and grafted Egyptians. Both were made to be circumcised. He made no distinction, meaning we can be safe in saying it was to all of the children of both the former Egyptians, and the first Israelites.
We have to look at this in context, because right before this, he was disputing Judaizers that claimed that the only way to be saved, was to first be circumcised, but he pointed out Abraham. That, first he had faith, and then he solidified that faith and sealed it by circumcision. Just as Abraham was, he said we are to be. He was making an example, saying, we are saved and justified by faith alone, but that eventually that faith would cause us to get circumcised. Not to save ourselves, but because we already were saved by Jesus - through faith.
Joshua 5:5 - Now all the people that came out were circumcised: but all the people that wereborn in the wilderness by the way as they came forth out of Egypt, them they had not circumcised.
This verse says that "all the people" that came out were circumcised. Came out of where? Egypt. All those that came out of Egypt. Egyptians also came out with Israel, and they were counted as Israel, because they followed after YHWH. This doesn't say, all natural-born Israel, except those born in Egypt. No, it said that all that came out of Egypt. This is including the Egyptians that came out as well.
It then goes on to describe those that weren't circumcised, as those that were born along the way after they had come out. So, since all the first generation was dead, and the second generation was alive, most of them from the second generation weren't circumcised. This makes no distinction between natural born, nor foreigner, because as Torah says constantly, they shall be to them as one born IN the land. That they shall be as a NATIVE born.
There is not one law for the Israelites, and another for gentiles. Otherwise, as someone else so wisely pointed out on one of these forums. If this was the case, then God would have had no ground to destroy Sodom and Gomorrah because they weren't part of Israel. They were gentiles. Nor would He have any grounds to give Israel the promised land, because as He says, it's not for Israel's righteousness that He gives them the land, but because of the unrighteousness of those being removed. They wouldn't be expected to live up to the standards of the law not given to them. His law has no limitations to who it applies to. It applies to all flesh, because His law is the only way we know what sin is, meaning, if it was only given to Israel, no one else would be sinning, because the very definition of sin wouldn't even be applicable to them.