A few reasons. My first playthrough, I played as male V nomad. For my second, I went when a female V streetkid. So, part of it was going for a different story.
Another part is Judy. Yes, people have made mods to allow romance as a male character but those just don't seem right to me. Judy's a badass, beautiful, crazy-smart, and one of the only characters in Night City that I could likely be friends with IRL. But friends/extended family is all it could be. She's very clearly a lesbian, in her character as you get to know her and even her choice and style of tattoos - the roses on her arm especially seem rather anarcho-sapphic to me. Using a mod to "make her straight" just seems wrong, like a violation of deep parts of who Judy is. So, my second character was a lesbian.
And finally, when I started my second playthrough, I was a bit thirsty.