In the grammar lecture, the sequence you understood was analyzed as a noun referring to the unstated subject of a command, where the subject is assumed to be the person addressed.

I hope you-all can make it to the meeting tomorrow.

When I asked him to send the file, he replied, 'right you are,' and emailed it immediately.

You beauty! He took that specky right on the boundary and slotted the winning goal.

This homemade smoothie is better for you than the store-bought one.

Of all the options, the grilled salmon is best for you.

Excuse you! You just cut in line without apologizing.

Oh, stuff you — I don't have to take orders from you.

If you lot don't stop shouting, we'll have to ask you to leave.

At the reunion, I bumped into an old friend and said how're you, hoping he remembered me.