"If it's all right for X to do A to me, then it would be all right for me to do A to X in relevantly similar circumstances"
"If it's all right for X to do A to me, then it would be all right for me to do A to X in relevantly similar circumstances"
"If it's all right for X to do A to me, then it would be all right for me to do A to X in relevantly similar circumstances"