Nowadays hetero has been redefined to better reflect gender diversity. Homo is same gender, hetero is different genders, even if the gender are not man and woman. This includes non-binary people in the definition, as long as they are not the same gender, is not homosexual. And to be honest, it ties better to the word, etymologically.

Also bisexual now means homo and hetero, not men and women. I’m still confused about pansexuality in this definitions. I also might have got something wrong in this explanation as I’m a cis straight dude, who listens to other people saying this things.