What? It's not derogatory. It's just shorter and in some ways better specified than 'American'. I also used the word 'American' in the same post! Just didn't feel like writing the whole thing out the second time. -_-
It is derogatory. Virtually no Americans call themselves "USians". It's nigh unpronounceable (it sounds like "US Asians") and only seen on the internet in the context of somebody with an axe to grind against America (as above.)
USAmerican is what I use to make it clear I don’t mean Canada or Mexico or Latin America. Some people don’t like it, because they think it’s unnecessary as most people assume you mean the USA, others don’t like it because they think the US is the center of everything so how dare you attempt to be inclusive of other non US American countries.
pleeeeease don’t do this. i was born here, i’ve lived here my whole life: i’m an American, or a USian, or any other label you want to use that marks me as a US subject/citizen. i really don’t want to be burdened in keeping up with which identifiers people use for me are supposed to be offensive v.s. neutral, especially when it doesn’t impact the meaning of the post. online communication is hard enough as is — don’t make it even more complicated.
And then you have people who suddenly must say Ukraine instead of The Ukraine, or must say Turkiye instead of Turkey and definitely don't even try to use any of the blue demonyms for any other country, but for Americans, yeah call "them" whatever... such hypocrites.
I don't care either way, but generally the term is used in specific context where the writer feels "American" would be too imperialistic as it excludes all others that live in the Americas. It devolves into debates about whether the US "stole" the demonym. Right or wrong, it's going to trigger some people.