I'm going to be very honest here, and it's something it pains me to admit, but as you've laid open your vulnerabilities you deserve the same.
There are two things which mean that in a room full of strangers I will gravitate towards white women.
The first is names... I struggle to remember names if I meet more than one person at a time, but I have a much better chance of being able to commit a recognisable name to memory. If a woman's appearance indicates she's likely to have a name which isn't very common in the UK, I fear I'm going to embarrass myself trying to learn it.
For example, I was recently at a conference with 5 women from our Indian office. They all introduced themselves to me. As soon as they'd finished saying their names I'd already forgotten them. I feel really rude asking people to repeat their names and saying it back to them like I'm poking fun at the foreigner... I'm really not. But it might look like that. So instead I just avoided spending much time with them individually, because I didn't know their names.
And that's on me, not their fault in any way, I'm the crappy one, who struggles enough with social situations without an additional challenge.
The other is language, and if someone's first language isn't English, although this isn't a skin colour issue, because a white woman is just as likely not to be native English speaking. But you mentioned being from a different culture so perhaps your first language is different. Anyway, I find it difficult to follow a conversation if the other person is struggling with English, my mind wanders at the best of times (again, my fault, no criticism of the other person), so when there are lots of pauses while the person hunts for the right word, I disengage. So if I hear a strong accent during my first meeting with someone, I might not seek them out later to spend more time talking to them.
These are both reflections of my privilege and flaws, but also my fears about looking bad to others. They are in no way an indication that I think those people aren't potentially lovely and would be great to know as friends.