Further, by stating that your actions were not “gender” based, you are admitting that they were/are gender-based. Let’s go through the logic:

A woman kissed another woman on your plane.
You allege passengers complained about that and that its your job to ensure passenger comfort.
You took no action during the flight to ensure the comfort of the alleged complaining passengers in regards to the issue that they allegedly complained about.
Ergo, there was no comfort issue during the flight, or else you would have taken action during the flight, as you admit it is your responsibility to perform.
Ergo, Ms. Hailey did not engage in any activity en flight that required that you take any action towards her.
However:
Hailey is a woman.
The person she kissed is a woman.
The kiss was not an addressable offense according to your own words and actions, leaving only one other fact to provide a basis for your negative action towards her: the gender of her and/or the gender of the person she kissed, or the gender of both of the women.
Ergo, the action you took, Southwest, was clearly based on the women’s gender.