Why is C=C launching electrophilic attack on Bromine instead of the other way round?

So during my lecture on reaction of Alkenes with Halogens, my lecturer used the example of $\ce{Br2}$ gas reacting with $\ce{CH2CH2}$. He mentioned that the $\ce{C=C}$ launches an electrophilic attack on the electropositive Bromine atom (the one that is nearer to $\ce{CH2CH2}$) and I'm wondering why is the $\ce{C=C}$ launching the electrophilic attack? Shouldn't it be done by the Bromine gas since the $\delta^+ \ce{Br}$ is electrophilic and **needs** the electrons so it attacks the double bond which is most electron dense?


