Then the least you could do is quote him, say something as "This should be your awnser" and then lock it.
If what
@Tacosbefriends (I tagged him because I want to know his opinion on this..) said is actually true, (and I see no reason for him to lie about it) and he indeed did inform all staff members that they should provide a reason when you lock a thread, this isn't allowed.
No matter what people say in the messages above, you should always add a reason.
If someone found a bug, a hacker, they ask for a rank or they got fasley banned, members say what the player should do all the time. Mods don't lock thread either without having a reason.
It's not that hard.