No.
CitizenGo is an offshoot of the grassroots Spanish organisation/lobbying group Hazte Oir ("make yourself heard"), founded in 2001 in Madrid. They've always had interest and support from people in other Spanish-speaking countries, which historically has mainly meant the Américas (I assume that is what you mean by "mainly used by Americans"). In 2013, they went global and chose an English-language name for universality. The days when their influence was limited by language or geography are long gone. I've seen their influence and the influence of similar faith-based conservative and radical right organisations firsthand in countries like Poland and Slovakia (CitizenGo actually provide translations of all of their publications in Polish and Slovak, which should give you a clue).
CitizenGo's values are (generally) trad, hard-line Roman Catholic. CitizenGo say they mainly champion “Christian” causes, which means actively opposing abortion, same sex marriage, euthanasia. There are a lot of people in Américan and central/eastern European and African countries that have an affinity to Catholicism and/or Christianity but have a much more traditionally "liberal" or "radical" approach - go take a look at the influence of liberation theology in all of these regions, just for a start. But there are not a lot of organisations defending or promoting liberation theology internationally or even locally, so people seek support where they can find it.
I dislike CitizenGo's values and don’t wish for their goals to be achieved, but I disagree that they are “dubious” (cloudy, unclear, obscured, in doubt). CitizenGo are clear and transparent about what they believe, support, and campaign for, and as far as anyone has been able to determine or prove they follow the law. They are completely transparent about their financials, and their funding is scrupulously grassroots.
If they are telling you (@DaveDave) that your donations will be ring-fenced for Caroline Farrow’s court case - do your due diligence, but I see no reason to be especially suspicious of this organisation not keeping their word. And if it bothers you to use their platform, perhaps go ask the other platforms that you would have PREFERRED to use why they seem to be routinely turning down or summarily deleting appeals related to women's rights.
More broadly: if you’re on the left or consider yourself “progressive”, or in the centre and consider yourself “liberal”, ask yourself why the left/centre isn't doing more to combat the tide of misogyny. Again, I don’t like Citizen Go, but I understand why desperate people embrace them, and I see that a lot more women are becoming desparate in this increasingly misogynist society. The alleged “left” has left a lot of very vulnerable people, including women, with no other choice. Why are more of us on the left or at the centre NOT more angry about, and more resistant to (and yes, I know some people here have done a great deal, thank you!) the overwhelming capitulation of “the left” (and centre), and of publicly-funded institutions, and of the private companies we support with our custom, to misogyny and rape apologism and the normalisation of rape culture?