Speaking as a single Gay Black American
United States (maybe also this applies to Canada too?) for Gay Black men:
Has more Black/Afro-Centric solidarity history and movement
Has more guys of all backgrounds/races who are aware of Black culture, music, slang, foods, history
More discreet/down low/fly by night/anonymous hookups/flings/sex
Racism exists, but due to free speech laws, and context, it is water under the bridge in most cases, and those being racist are of course shunned, and you'll have plenty of people being empathetic to you.
Guys who are not interested in you, make it very clear, sometimes in a harsh, mean, cruel way etc. But at least you know where you stand in the community, and it makes things easier etc.
Love may be harder to find, but when it's found it's genuine
If you want to date/associate with only Black men, stick to the Atlanta, Chicago, DC areas.
If you're a masculine, and live in a major city, as long as you don't care what race the guy is, you should have no issues.
If you are feminine, or a more artsy/preppy/open minded to White/other races of guys, Black guy, and preferably feminine, you could experience issues altogether, but could luck out in more metropolitan area, but also in more outskirt/dismissive areas.
United Kingdom (Maybe possibly Europe and Australia too?) for Gay Black men:
If you are someone that likes to travel, has the finances/means to travel, and can familiarize yourself with English/British/European/Australian/foreign country/land customs, you'll be fine.
You don't mind being a teacher/explaining Black culture to people who have little to no understanding of it.
Guys who are not interested/attracted to you, will still be friendly, and chat, let you cuddle, hug, drink, sleep over at their house, etc. with you.
Racism exist, but it's more then hating that you're American, or them hating that you're posh, or not posh enough. Racism accusations in England are strong/serious, so unless there is enough evidence racism is at play, it is usually downplayed. But racism in England of course isn't okay or allowed.
Love may be easier to find, (especially if you're American) but you may have to do a lot of teaching to your partner, and things might more slower, as opposed to faster American romance/love.
If you are masculine, people might think you're an athlete or VIP/Celebrity person, which might help you to find people to date and make connections with.
If you are feminine, (and especially also American) as long as you don't care what race the guy is, you will have guys trying to connect with you, based on curiosity and them wanting to know you better.