Usopp hasn’t spent a thousand chapters getting a hard on for every woman he even thinks about or otherwise let his dick get in the way of fighting for his life, this is the exception rather than the rule; don’t act like there hasn’t been a very strong, consistently repeated precedent set for that kind of lascivious behavior from Sanji
The actual problem is that Usopp has contributed fuck all for over half a decade now, and it's not getting better in Egghead.