It may not seem unfair to you and I, who have skills and knowledge that keep us highly employable.
I think in its totality trade has globally reduced poverty, and improved lives globally. But that doesn't mean that there are not people who have been harmed by it, and see it as unfair. If your grandfather and father worked in a steel mill, and you worked in that steel mill and got let go because "its cheaper in China" then I can understand why that person may not feel that it is fair, to be sacked from everything they know. Whose family helped build and run that mill, through blood, sweat and tears.
Historically, elites have tried to mask this by saying that these low skill jobs will be replaced by higher skilled and higher paid jobs, and through training those low skilled works can just take these higher paying jobs. The rise in Trump is in large part due to the perceived callousness of elites on those who have been made worse due to trade. I think this is the key failing through-out the Anglosphere. How to get unskilled people into work, how to enable them to maintain their dignity, and do an honest days work for an honest days wage.