usually there is no tax when you recieve it on doorstep, as you mentioned, you got it under 7 days so you maybe used DHL or any special courier service thats why they also charged you.
A normal AliExpress shipment ( free shipment via China Mail ) takes minimum 22 days to arrive ( you can see your order tracking too )
I know how AliExpress works
I was charged like $2 for delivery from the motospeed official store
Here it was delivered by "skynet"
Those are the people who took the taxes
I don't mind, to me it was worth it to get it in 7 days
I was afraid I wouldn't get it at all so $2 plus the tax I paid on delivery is definitely worth it in my opinion