You first have to ask why the author would have a parody NRA in a chapter.
The NRA
existing, under an altered name, isn't "parody".
The Statue of Liberty cracking and gun owners being hurt by the Gun Devils power is heavily implied to show how Destructive America is.
Firstly, the chapter
ends with those two things, so there's zero indication that what you came up with was the intended implication. Secondly, did you already forget that the Gun Devil is distributed between several countries,
including Japan? Or that the Japanese government not five chapters ago was ready to issue the order to sacrifice 10,000 children to summon the Old Age Devil so that Chainsaw Man could eat it?
And the crazy thing to me is if the author feels like that about America why tf is Chainsaw Man so heavily marketed to Americans.
Even if I grant everything here, the answers would be:
1. Because American manga readers have a preference towards
Chainsaw Man, and Viz capitalizes on that preference.
2. Fujimoto has no contact with, let alone control over, the marketing strategy of an overseas subsidiary of his publisher.