They partly were, they're just not given nearly the same attention and are often terribly outdated and less engineered.
Also they aren't tested as thoroughly, there was a call for hardware by the FreeBSD team not that long ago that I can't find, they simply don't have the same kind of resources.
Most FreeBSD dev is focused on server hardware like for Netflix and its ilk, I don't know many other people who use it as a daily driver.