Using someone’s correct pronouns when speaking to them (and about them! because it means nothing if you misgender and disrespect them behind their back!!!) really is the actual bare minimum of respect and decency you can show them as a person.
It’s a non-optional thing. Either you respect them, and you use the pronouns that they tell you to use, or you don’t and you don’t.
It’s not hard, it’s not difficult. It’s not complicated. You just use the right freaking pronouns. And without trying to play 20 Questions with the person about it! You’re not entitled to an explanation as to WHY this person goes by these pronouns. You just use the pronouns that they tell you.
Trans women and trans men, nonbinary and genderfluid people, gnc people, he/him lesbians and she/her gay men, all of you, an explanation of your gender identity and why you use the pronouns that you do is NOT a prerequisite for respecting you and your identity. You don’t owe anyone an explanation, you don’t have to bare your soul to get respect.
If someone is a decent person, they’ll be respectful from the start.