Newcomer / Intro Attacked by Feds.... why?

[DravenAU]

I am clean (not Wanted).
I went into a USS and found two Feds and one Expert Wanted Viper. I figured I had a chance of taking him. I watched him fly aimlessly for a bit then opened up on him. We started fighting and I got his shields down and was laying into him when the Fed Anaconda opened up on me. For some reason when I'd attacked the Wanted NPC (he had a name), they turned red/hostile.
I don't have a warrant scanner, so for him to show up as Wanted means he was only wanted in this system. The Anaconda wiped me out in about one salvo. My first death. Needless to say I felt a little hard done by. Corrupt Feds.
I still have no fines, bounties or anything against my name. I have no idea why they attacked me. I'm confused.

Also... why is it that when I approach many USS I'll start slowing down but then my ship will speed up and accelerate past the USS and make me come back? (this happened prior to me getting into the USS that just killed me)
I've tried keeping it in the blue section.
If it it says SLOW DOWN and I pull the throttle back it just goes faster.
I'm rarely approaching a mass when this occurs.
The only way to make sure I don't overshoot targets is to keep the throttle way below the blue zone and crawl to them.

 

[hitkill1]

To explain a bit more what happened is:
You attacked a Wanted that is part of a Faction.
The Federal fighters where also part of that faction and saw you as a enemy from there friends so killed you.

Best way to check this is before you start hunting always check the orange NPC (Or green depends how good the relation ship is)
If they are part of the current leading faction ignore them. (This can be found on the right panel 4 first tab scroll to left or right with a d )
If not attack them then when you got all the other factions red you can pick them apart easily.

This is something i always do.
This is without saying only attacking wanted.

For the second part you aren't speeding up.
The auto pilot will make it so you can't go faster at a certain range.
But by doing so if you are already going faster then the max speed it will look like you speed up but if you look at the actual numerical value of you speed you are slowing down.

Also the blue section is the optimal turn rate not the optimal speed.
Best what you can do is keep the distance at 8 sec and keep slowing down.

 

[DravenAU]

Many thanks.
My misunderstanding about the Wanted tag. I believed that Wanted meant they were wanted within the faction space I was in. I will verify their faction versus the Police around me in future.

Thanks for the throttle explanation. Again, I was aware that in normal space the blue was optimal turning, but someone had mentioned that the blue in Supercruise represented an auto-speed zone. I will ignore that information and just throttle manually.

I appreciate the explanations. =)