Many think about them as about cheaper "ersatz" substitutes for normal products, invented in the USA to feed the poor negros.
That's not correct about Soy milk. They are not like that in the USA.
The problem as I understand it, is the opposite. Many uneducated people (often black) choose unhealthy food and ruin their health with fatty fast food and sweets. The question about race in the USA is quite complicated and I don't fully understand it. But I can tell you one thing: You should not use the word "negro", it is considered racist and people get *really upset*, including most white Americans.

You should say "black" which is acceptable in the UK, or I think in the USA, the ideal expression to use is "African - American".

However, it is bad to drink too much soy milk, particularly for men.... it contains female hormone "estrogen". Rice milk and Oat milk are better alternatives!

And about prices in Belarus: The stuff that is made locally is really cheap and absolutely decent quality. Not the top end stuff obviously, but there is such a big difference in prices there, that it makes a lot of sense to buy local products unless there is some strong reason not to. I think many people have no other choice than stick with local products. I imagine they have a lot of traffic of Russians and Ukrainians who simply go there to by basic products cheaply!