Lelddos spilled Minecraft accounts from servers he DDos Change your password 2-5 days. (Refer to Jarroyonapples thread)
If yu want you can delete this thread or lock it or anythin you any you want to do with it...your choose :/
There is no way for servers to obtain passwords of Minecraft accounts. There is many lists out there with Minecraft accounts and passwords, likely the DDoSer obtained one and falsely reported that they were from the servers he DDoSed to make people freak out.
That is your choice, I believe Mojang told everyone to change their passwords due to Heatbleed, so if you haven't recently then it might be best. But servers are not responsible for lost/hacked account information.