Roundabout slip road that you continue don’t stop

Was I justified to beep and then signal to a driver in front that they could continue on so as to stop the hold up in traffic?

Hermi gate Edinburgh there’s a side road that avoids the traffic lights and that you can continue on. Someone stopped so I beeped to get their attention and signal that they could continue (also to avoid collisions as it goes into a 50mph zone) and they did move after a bit of you can go signals and others beeping.

They then stuck their middle finger up at me out the car. Like really you’re the idiots in this situation. No L plates etc so wasn’t even someone learning.