"master/slave" evokes the unhappy history of slavery, which people care about to widely varying degrees.
"leader/follower" or "primary/replica" are much more neutral terms that won't prompt negative emotions in many people.
People who choose one of the latter two options do so either because they feel it is more accurate, or because they wish to avoid the negative connotations of "master/slave", or a mix of both.
It's better to stick to tried and true terminology that everybody understands than to needlessly introduce new and redundant designations for concepts that have been in use for decades, just to avoid upsetting rather irrational American sensibilities.
Leader/follower and primary/replica are common terminology now. It's unfair to paint the sensibilities as irrational - this is exactly an example of the kind of nonchalance that helps lead to underrepresentation of minorities in tech.
You might not care, but there are a lot of people that do. Taking steps like this improves the comfort level others while affecting yours none. Why is that not worth it?
So now we have three pairs of terms that apparently mean exactly the same thing. I'm sure that whatever "minorities in tech" are more interested in not being needlessly confused, than not seeing the word "slave". Who would even think of this in terms of human slavery, and why would it be connected to american minorities only?
