I went back and watched the video and it does appear that he started speeding before the sirens were on. But that doesn’t change any of the other facts; the cops continued the chase even though it endangered innocent lives in the way over a stolen vehicle.
The kid had committed multiple major felonies in under four minutes.
He was driving like a maniac and was a danger to all.
I don’t know that not chasing someone who is a maniac behind the wheel helps at all. Could in fact give enough time for them to instead kill a bunch of other people.