I am left-handed and I play left-handed. Isn't that awful?!
Actually I am fine with left-handers playing right handed and I recognise it has some advantages. But playing left-handed, whether "upside-down" or "mirrored" works just fine too.
I think left-handers vary considerably in their experiences with what felt natural and how they were taught. For example my parents taught me to use a knife and fork right handed because the complex act of holding and cutting needed teaching and they both did it that way. But I learned to use a spoon left-handed because early on I grabbed one with my left hand and was away.
Cricket right handed- dad taught me. Hockey right handed (that's how hockey sticks are.) But all racquet sports left-handed. Scissors right-handed (left-handed versions were rare as hen's teeth then.) Drawing and writing left-handed (pencils don't mind and thankfully neither did my primary school teachers nor my left-handed mother.)
When it came to guitar I picked up a teenage friend's electric "upside down" and he didn't say "that's wrong" but rather "Oh like Hendrix. You can restring them. And actually you can get left-handed guitars; not easily but you can." So, with no one arguing and just my patient friend informally teaching, I bought a left-handed bass.
Our brains are very plastic; I have no doubt I could have learned right-handed. But I don't regret learning left-handed. (I wonder if Professor Delcamp regrets playing left-handed.) It has probably saved me bankruptcy buying many very attractive guitars. However I do have 9, including 4 classicals so it's not been too much of a problem! The search is irritating at times but doubly rewarding.
Two right-handed tutors took a left hander in their strides. Hopefully the rest of us can too.