I'm aware that mainstream archaeologist don't find evidence of an exodus of "Jewish" people from Egypt via the Sinai into Caanan. I personally don't buy their arguments (no dung piles in the desert, no artifacts found, no identification of Mt. Sinai, etc.) But I accept that no evidence is no evidence.

There is, as far as I recall, evidence of an "exodus" of sorts of the Hyksos from Egypt, but not any (solid) evidence of it happening in the manner or time described in the Biblical account.

I'm not sure I buy the Israel = Hyksos theory anyway. But this gets fairly far from my question, which really related to what the authors of this particular paper allude to, but don't say explicitly. They use some fairly strident language to describe what it is they are not talking about. I was just curious what that was, and why.