Yes, but the US is bigger. Now do US vs rest of the world for example. Or take Europe as a continent and not many countries. We can draw arbitrary lines on maps and the bigger area will tend to have more migrants within it just because it is bigger. To make a fair assessment we probably need to do migrants per capita or migrants per square kilometers.
I did the math on the latter. Higher numbers mean more migration per km² of land, I made US 100% to allow easy relative comparison:
United Kingdom 1076
Germany 918
Japan 694
Italy 653
Spain 519
France 407
United States 100
Saudi Arabia 91
Canada 59
Australia 34
Now we can also do the same for per capita (which is a bit paradoxical, because that means bigger populations will get a lower index, but migration increases populations...), but that tells us where the smallest populations have to deal with the biggest number of migrants:
Canada 494
Australia 333
Saudi Arabia 193
Spain 186
Germany 136
France 132
United Kingdom 131
Italy 115
United States 100
Japan 73
As you can see the US is very close to the bottom on both of those lists.
Now if we wanted to make that even fairer it would probably be good to have a metric of migrants per km of built-on or habitable land or something to avoid skewing results for countries with a whole lot of inhabitable nothing in some areas. Canada and Australia are on the bottom in the first list (big countries with little population in comparison to their size) while they are on top in the per capita list.
As you can see it isn't as easy as it seems at first. What do we want to look at? Is it about land use? Is it about how big of a fraction is migrants? Or do we want to look at migrant per USD of GDP to see who would have the best/worst capacity to support migrants? Maybe we want to look at job markets?
All of that changes as you want to change the story, but what does not make sense is to just use absolute numbers based on national borders.