You missed an important part. Impure animals by your translation was made clean not the unclean. Impure is Koinos in the Greek it means common. And if you must impure. If translated impure then typically it is in reference to things that were ceremonially impure. Like the vessels for the Sanctuary before they were cleansed. Not the animals that God had said were unclean. Peter said he never partook of anything Common OR unclean. The word "or" makes a distinction between the two. Then God said call nothing that he had cleansed Common. No mention of the unclean By God whatsoever.
Acts 10:14 But Peter said, Not so, Lord; for I have never eaten any thing that is common or unclean.
Acts 10:15 And the voice spake unto him again the second time, What God hath cleansed, that call not thou common.
Peter refused, similar to Ezekiel when commanded by the Lord to eat bread cooked over human dung (Ezekiel 4:9-14).
Concerning common or unclean, there may be a subtle difference, but it is difficult to determine precise differences in meaning based on existing contexts.
Additionally, the same Greek word for "common" was used in relation to eating unclean meat in 1 Macc 1:41-64, in terms of sacrifical animals AND eating unclean meat, so I don't understand the point. Either word can be used to refer to ceremonial impurity or unclean meat laws. However, it doesn't make any difference because God told him to rise and eat...therefore there was a lesson God was conveying concerning food consumption, as well as the Gentile's status before God. Like I said, the two are associated because some laws within Israel were meant to separate them in a social context to prevent the Israelites from falling into idolatry. It is also significant that meals in pagan trade temples were a problem in the early church, which led to immoral behavior and idolatry with some.
The New Covenant age of salvation meant full inclusion of Gentiles and fulfillment of OT laws of ritual purity. See Mark 7:19, Col 2:16-17. This means that the way for table-fellowship has been opened between Jew and Gentile.
The commandment regarding unclean meats was meant to create a social barrier between the ancient Israelites and the Gentiles, to avoid idolatry.
Gentiles were considered unclean by virtue of what they ate.
Socially, relationships are hindered when the two parties don't share the same diet. Gentiles were generally idolaters, so by intentionally separating Jews and Gentiles socially through diet, Israel was kept "holy" or separate from the surrounding nations.
Ephesians 2:13-15 relates to the removal of such prohibitions, and says that we are one man in Christ, Jews and Gentiles. Mark 7:14-19 hints at this, prior to the death and crucifixion of Jesus.
Additionally, there is complete silence regarding commands for Gentiles to observe clean/unclean meat laws (or the Sabbath). As a former Sabbathkeeper, I don't find it credible that Paul would have remained silent on this issue. Obviously either issue would have presented problems for slaves with Gentile masters, as they would not have had the power to dictate either their diet or the days that they rest/worship. Yet, the Judaizer expects us to believe that such new practices were simply accepted by Gentile masters without any recorded disturbance in Scripture.
Judaizers apparently make a huge assumption that slaves had civil rights like freedmen possess in modern day democratic societies.
By the way, I am not claiming Maccabees is inspired, but contemporary Greek usage is valuable in giving us an idea on how the word for "common" can be used...and it is used both in a ceremonial purity sense, as well as unclean in terms of meat in this section of Maccabees.