Comparisons to Nazi war crimes not backfiring or having a net positive effect are very rare.
I think that in this case the image is effective as a counter to the argument being presented in the campaign.
- It shows that there are other categories of people who have legitimate reasons to want privacy and not to trust the authority of their country.
- It does it in a way that would not require explanation to anyone familiar with Anne Frank (including lots of people from UK).