Powerlevel as only argument jeez.
Luffy was said to be the master mind behind the WCI invasion ,he make the Germa his ally and joined hands with another worst generation member . Lastly he defeated two of her commanders.
Plus don't forget he has the grand fleet.
That's why his bounty was high because he got closer to what a yonko has .
Luffy was only insulted by having law/kid bounty those two have nothing crew ,territory,army wise .