Speaker wire and connection (Why was it done like this)

So this is more a question to learn why and not questioning the tech team.

I reciently stripped my HT room because I needed to redo the floors in the home, I am now reinstalling all the rooms to original state and noticed the wire conection used on my HT... I have seen this before and noted it was different but never till now wondered why it was done like this.

all 5 of my speakers in the HT system have a 4 core cable with banana plugs (White, Red, Black Green) feeding from the AV receiver to the speakers, on the Receiver end the White and Red are together in a Red banana plug and the black and Green are together in a black banana plug, on the speaker end the speaker has 4 contact points (2x Red and 2x Black) but the reds have been bridged and so have the blacks and then red cable into red point and white cable into the second red point, and the same with the Black and green both to a corresponding black point on the back of the speaker

Why have they connected white and red on the cables at the receiver but kept them separate at the speaker even with the bridge plate