"Now why are you crying?"
Alex became confused by White's sudden crying, And wasn't able to understand now why she was crying.
If it was Isabella then maybe it was understandable that too hard as the system says she herself not making others cry rather her passive pulling out the all negative buried emotions of people in her surroundings.
All others were crying non-stop because they held back and buried all their negative emotions deep in their hearts, not allowing to come out.
And so when she brought them all back at once, They could not able to control like they used to before and so can only let it all out.
But Isabella live with White since she was child, So there can not be negative emotions being buried deep in her heart as if there was White's presence would have pulled them out.
It did not matter that she is A-Rank asakned, The passive of White able to affect two S-Ra k back to back, There is no way Isabella would be immune to it.