It is. What more? They Novas? There is 7 more not counting Zoro and Killer.
Kidd is last second addition on Sabaody. Parallels between them exist only in Kidd's fans headcanon.
Dude doesn't hold a candle to Luffy.
How about the fact that:
- Luffy and Kidd are the only Supernova with conquerers haki
- Luffy and Kidd are the only Supernova captains with a Supernova vice captain
- Luffy and Kidd are the only Supernova who have expressed the dream of being PK
- They are the only Supernova who have faced multiple Yonko
- Luffy looks up to Shanks, Kidd hates Shanks
- Shanks specifically taught Luffy to ignore people who laugh at him, Kidd specifically notes that he kills people who laugh at him.
- When the Supernova were introduced Oda coincidentally made specifically only Luffy and Kidd have a bounty in the 300 millions
- Luffy has black hair and wears a red shirt, Kidd has red hair and wears a black shirt.
And there are even more. But sure all these parallels are DEFINITELY coincidental and are just “Kidd fans headcanon” lol. “The rock scene is their only parallel.” Sure buddy.