"The people who think it's most important of all are the people who disapprove of it."
Social conservatives don't want transwomen using the women's bathrooms because they don't think that they are actually women. That's the only distinction that they care about: biological sex. Everything else is fiction to them.
Bear in mind that this is a simplification of the stances of millions of people, all of whom are different. Some will more readily admit to the existence of transpeople and homosexuals.
I'm not sure where we disagree. As you say, conservatives think that the difference between cis women and transwomen is very important, as they believe that transwomen are not really women.
"The people who think it's most important of all are the people who disapprove of it."
Social conservatives don't want transwomen using the women's bathrooms because they don't think that they are actually women. That's the only distinction that they care about: biological sex. Everything else is fiction to them.
Bear in mind that this is a simplification of the stances of millions of people, all of whom are different. Some will more readily admit to the existence of transpeople and homosexuals.