It makes sense. If you take a very evil event and say it is similar to a normal everyday experience, then you are implying the evil event wasn’t particularly evil.
For instance “Harold Shipman was only like a hospice nurse”, or “people who protest are the same as arena bomber Salman Abedi”. It is offensive to trivialise evil by saying it is similar to something not evil. These statements are not only offensive to hospice nurses or protestors. They are offensive to anyone who understands the evils of the events they are compared to, because they minimise and trivialise those evil actions.
It is offensive to trivialise the holocaust by comparing it to current UK government immigration policy. This is especially true of the Nazi period in Germany, more so than my previous examples, because of the long history of holocaust denial and antisemitism across the world.