I have many thoughts about Slam Frank, and believe it falls way more in the category of trolling that parody/satire/etc, and I do not find it artful to simply shock. But others feel differently. That said, The entire existence of Paddington is completely based on the kindertransport: "Paddington Bear's iconic arrival is rooted in the tragic history of the Kindertransport. Creator Michael Bond modeled Paddington’s situation on the thousands of mostly Jewish refugee children who fled Nazi-controlled Europe for the UK in the late 1930s. These children arrived at British train stations carrying small suitcases and wearing identification tags around their necks."
To me, the Slam Frank ad, in believing its clever, speaks to how little the creators know or understand history, and are inversely confident in the points they are making.