There seems to be an assumption that "master" is always paired with "slave", but not only is "master/servant" a more common pairing, "master" is obviously a very common word/prefix/suffix with various meanings whose usage normally has nothing to do with subjugation of anybody.
A chess grandmaster does not imply the existence of chess grandslaves. The Sega Master System didn't enslave other game systems. A master key is just a key with wider scope than the regular keys.
A chess grandmaster does not imply the existence of chess grandslaves. The Sega Master System didn't enslave other game systems. A master key is just a key with wider scope than the regular keys.