But the person who gets the flag cannot get enough points to get first.

If obtaining the flag means being the champion, then if the person who gets the flag thinks: "Anyway, I'm already the champion. I'm lazy, so I'll just idle and won't even bother stopping you guys," then the one-versus-many competitive dynamic would be lost.

I think whoever gets the flag and becomes the shooter should get the most points. Then, the rest of the players race for 2nd. Seems unfair to punish the winner.