A company deciding not to transact with someone is not analogous to a government preventing its citizens from accessing portions of the web.

My comment states a specific analogy, which is that a lot of the excuses people give for the former also apply to the latter. You can't refute this just by stating that it's "not analogous".

I suppose they’re speciously similar, but the argument at its core is “people should be able to freely associate” which cuts against this decision by the Nigerian government.

The idea that companies should be able to control governments is a very american idea, and is pretty much not accepted anywhere else.

When a website actively supports destabilizing forces against a nation, the least that nation (and it's people) can do is to block said website.

It seems obvious to me that no matter what you personally think of e.g. a restaurant refusing to serve food to someone or even a group of people, the federal government issuing and implementing a decree (all within a matter of hours!) that bans all citizens/residents of the country from even entering said restaurant is a ridiculous overreaction and a gross abuse of state power.

I mean obviously when people say that it is a rhetorical devise to win an argument. I mean the people saying that are saying it exactly because it is bullshit. It is hard to argue against exactly because it is such bullshit.