“The vision was meant to show Peter that gentiles were going to be given the holy spirit the same as Jews. “
So why did he tell Peter to kill and eat instead of saying “Gentiles will get the Holy Spirit”? I don’t think God would say “Do this but don’t do it”
Who knows? I can speculate. Peter was hungry. Peter was very observant about obeying the Lord when it came to not eating the foods the Lord said not to eat. Yet he was NOT observant in treating gentiles the way the Lord said to treat them...with love and kindness. Peter REFUSED to kill and eat because it went against the teaching of Christ whom he personally learned from and it went against scripture which he was more than familiar with.
Regarding gentiles Peter still didn't get it despite scripture telling him to love strangers and despite learning from Christ that love of God and love of neighbor were the two greatest commandments.
So perhaps without the vision Peter still wouldn't have "got" it. He might have refused to go with them when they came to the door. Who knows? We can ask God one day.