Whitehat was a word previously used to mean that they may use the same way, however they are still the "good guys", and this is no different.
A whitehat hacker is someone who discovers (or attempts) exploits for good use. OpenBSD users/programmers often tend to be
whitehats, although still a large number of FreeBSD users/programmers may be whitehats. In comparision I would say more OpenBSD users/programmers are whitehats.
Often when a whitehat finds an exploit, he often informs people as needed. IE: FreeBSD security mail list, OpenBSD security mail list.
At the same time I would assume more Linux users are blackhats due to the large number of pinhead users while most
Windows users tend to know even less and primarily stay out of the "game" (this is no game, like blackhats think it is, you just wait until they come upon a server that does remote logging).
Blackhats are often pinheads who have
nothing better to do then attack people to prove how "1337" they are.