Yes, motivation does matter, and in the example I gave to you where facts are at hand, there is no discriminatory intent. The Constitution’s protection of racial and religious groups is organized around the concept of discriminatory intent. I realize you have not studied US federal constitutional law, but the intent was privacy/discretion, and not exclusion based on race. And I should remind you that there is a privacy right here that is worth preserving. When privacy is invaded, a tort is committed, if certain elements are met and the privacy right has not been waived.
In the example I gave of the Asian lady of a very specific ethnic group- let's say Samoans- her refusal to see ANY Asian, as opposed to just Samoans, to preserve her discretion and privacy within that community, could be contended to be insufficiently narrowly drawn. One could argue there is no discriminatory intent when she just excluded Samoans, but there was discriminatory intent when all Asians, including non-Samoans, were also excluded. And yes that is a real life example although she was not Samoan but another Asian ethnicity.
No actionable discrimination there. Because discriminatory intent cannot be proven.