I guess I'm a little late to the party, but I think this article might be of interest to people on this site: http://africasacountry.com/africa-has-always-been-more-queer-than-generally-acknowledged/
The really interesting/perplexing thing about a lot of the anti-gay rhetoric is that a lot of it is conflated with nationalist/jingoistic sentiment; i.e. reaffirming national identity and preventing it from a perceived corrupt Western influence. We also see that in some of the dialogue surrounding the Uganda's more punitive law; in response to criticism about the law, the Uganda president more or less responded with "Well if it's wrong, we as a nation should be the ones to figure that out." It's an interesting assertion; it almost seems as if the Uganda president is using the anti-gay law not as a measure just against gays within the country, but also as a refutation of Western influence.
Thus, a perhaps more interesting question would be, why now? Nigeria for instance, is a nation struggling with a myriad of problems: corruption, lack of infrastructure (for instance everyone there that can afford it has a generator, because there is rarely any electricity), sectarian violence in the north, a failing higher education system (my cousin, who, like a large part of my family, lives in Nigeria is an electrical engineer, yet has been in school for about 6 years now just because of frequent disruption that goes on due to university strikes etc... and the worst part about that is that now, unlike even 40 years ago, if he were to emigrate, his degree is barely recognizable at many U.S. institutions). Moreover, Nigeria at least is conservative; one wonders how "visible" gay culture even is within the nation (probably more so in cosmopolitan areas like Lagos, but I think its reasonable to assume that its less visible than in the U.S. for comparison) IMO, this seems like an attempt by Goodluck Jonathan to distract from the very real and pertinent problems facing the nation by passing a bill that people support whether because of homophobia, or because it is being sold as a way to "Keep Nigeria Nigerian"
That being said, I think its also important to be critical to a lot of the coverage of this issue. Much of the coverage has been focused on the backwards nature of the law, which is fair because it is a gross violation of human rights. That being said, very little of it has focused on the international perspective; for instance at least within Uganda, there is some evidence to suggest that U.S. evangelical pastors have frequented the country, encouraging homophobic sentiment. I believe the film "God loves Uganda" talks heavily about that (trailer: ) Even less has focused on is the anti-West slant to a lot of this law, and I think that is an important area to suss out, only because it begins to bring into the dialogue questions of national sovereignty, the drawbacks to foreign intervention, and at points, the hypocritical nature of the coverage which, while trying to paint a "backwards" Nigeria and/or Uganda, fails to see how it is feeding into a larger racialized narrative. It reminds me, actually, of a lot of the controversy surrounding India over the summer I believe about gender issues. It would be wrong to assert that there aren't very real gender issues within the nation, and that they express themselves in ways that are more extreme then what we are used to in the West. But too often media narratives leave out a lot of nuance, essentially just creating a binary between bad/backwards East and progressive West, that sweeps under the rug our own cultural gender issues.
This is all to say that I think its important we are having these discussions about gay rights within an international context. I think, however, that it is useful to look for those people who come from that nation and perhaps give greater weight to their analysis of it, because they are directly immersed in their culture and can, in effect, act as better cultural translators for Western readers then Western media which merely perpetuates the same tropes. A good article by a Nigerian author on this bill follows: http://www.thescoopng.com/chimamanda-adichie-why-cant-he-just-be-like-everyone-else/
In regards to Nigeria reputation abroad... that's a difficult question. To be honest, a lot of Nigerians have bad reputations even within Africa; its been a joke in my family to say, that when people ask, just say you're from Ghana. But, as with all stereotypes, it is only a percentage of the population that gives rise to the whole. I also think the question is interesting, because, in my experience, I have always found that, at least in the U.S. the reputation of Nigerians has been relatively positive, outside of the familiar "Nigerian prince/email scam jokes"; For example, though this is a really problematic book for a lot of reasons, Amy Chua's newest book The Triple Package identifies Nigerian-Americans as an "exceptional" group within America (http://www.theguardian.com/books/2014/feb/16/the-triple-package-amy-chua-digested-read) I haven't read the book, and I wouldn't recommend anyone read it, but it at least is an example of some"positive" stereotypes of Nigerians. It's difficult for me to say anything too specific about the case in Ho Chi Minh City, because I know very little about it, but in some research I've done on immigrant experiences/narratives, I found it increasingly apparent that the host nations perceptions of the incoming group are often culturally specific, and reflective as well of the economic environment within the nation, as well as how obvious signifiers of difference are. I would be curious to learn more about that particular case though... it sounds a little bit like what the Romani population in France might experience?
I might also post this comment on my own page as well, but I'm glad that we're talking about it.