Sanji was in base, without his Raid suit or the genes. Black Maria has haki, but do you know that Haki isnt always visible. Also she is a tobbi roppo, so she is tough and the ability to use haki to protect one self or something of that caliber is essential to survive in the new world.
2. Him using haki is irrelevant because BM didn't use it neither.
3. Haki stopped being invisible after the TS.
4. She is still one of the weakest Roppo's out there. Robin, who didn't use haki neither tanked her attacks fine and you are telling me that Sanji can't?
Man, going by what you said, it seems that Sanji is stronger for me than he is for you. Being nerfed by a fodder+, what a joke.