This is a stupid question, but please help.

[Nisch]

You can use focus to remember a target or someone from your team:

/focus Moderator

Now 'focus' can be used as a unit in other macros. This way you don't have to hard-code "Moderator" into your macros, which makes your system a lot more flexible.

Then you can assist a friendly unit by using the focus:

/assist focus

or you could assist directly giving a unit name:

/assist Moderator

And then it's just the usual casting:

/cast Ban

Because of the assist, you can basically attack whatever enemey that focus(Moderator) is attacking.

That's some good lolz right there.