It doesn't for people who haven't grown up with Looney Tunes. You're on a fairly international site here. Similarly, you can't expect everyone's education about the Holocaust to have covered this specific thing in a way they'd reliably remember and avoid an embarrassing mistake like that.

Now, if the quote had been "Arbeit macht frei" I would understand the outrage, but to me the English translation sounds more like a reflection of the Calvinist/Protestant work ethic from the time when the saying was minted, at least 100 years before the Nazis rose to power. To some people the quote in itself holds appeal, and why shouldn't it? If read without context it is actually quite inspiring.