Why does this game have to have team damage?

you say its obvious, but even the example you give isn't obvious.
this game has really weird roadkill detection, on your screen he swerved to run you over,
on his screen he might have swerved to avoid you and appeared to miss you by 10m but still got a kill,
roadkill hit detection is REALLY weird.

this for example, i see the guy running so i take a long arc around to avoid him by 10m and...he's dead.
on his screen i will have mercilessly drove right through him.

there are so many times i'll swerve last minute to avoid allies who run into the road,
but i'll get a roadkill even though i apeear to have avoided them.
on their screen i've swerved to run them over.

in short, you probably c4'd an ally who was trying to avoid roadkilling you.

That kind of TK is very easy to explain actually.

Most hit detection in the game is clientside. You hit them on your screen, it's a hit even if on your opponents screen you miss.

Vehicle ram detection happens victimside. If you hit on their screen, you hit them even if you miss on yours. Because of latency it means your victim is a bit farther than where you see them, and you are better off swerving through them than out in front of them.

This also explains situations like driving with a Flash through a group of vehicles. If your flash hits them on your screen, you are the "victim" and get killed. If they hit you on their screen while you miss them, they are the "victim" and still damage and kill you.

the 2 main reasons snipers shoot friendly's by accident
- they snipe from behind there friendly's back and the players have no choice then walk in front of the snipers cause they want to get closer to the battle
- snipers want to farm at a bottleneck where both sides fight in CQC

this is not the place to be or shoot at as a sniper, i prefer snipers to cover my flanks and shoot what i don't see
you better be far away if you kill me that way without apologies
if i could get my hands on you i would slap you with my keyboard, but i can't so the next best thing is TK you

Honestly, it's a good thing there's friendly damage, or else I'd just tell my teammates to lob sticky grenades on my character and try to hug the nearest cluster of enemies or enemy MAX. Or I'd do the same to my allies, turn them into living grenades.

Nothing about the above two scenarios are unique to snipers. Other guns simply don't do as much damage. I am not responsible for a teammate who does not have the good sense not to walk in front of someone while he's shooting, no matter what gun they are wielding.
Nor is the game made up of pencil-thin lanes from the Spawns to the fight where you must run. Pay attention and remember bullets have the right of way no matter whose barrel they fly out of. I'd rather compromise and be alive at the fight than be at the spawn screen with the moral High Ground.

That experiment would end in tears. There is no need to buy animosity where none exists.

Yep, but it is still freaky, i've driven right through stationary enemies and it's done nothing, i've driven behind allies (because as you mentioned, a lot of the time they are further than they appear to be) and still got a TK.
It's a really weird and freaky system.
So when someone uses friendly roadkilling as their example of a deliberate TK because the guy appeared to swerve to hit him,
I remain sceptical.

It'd be great if friendly fire did 50% reduced damage, including bumping into to friendlies in a vehicle... instead of doing more damage to a friendly unit in a vehicle than you would if you hit an enemy player while moving at the same speed (while driving a vehicle).

You probably havent had an entire platoon kill you in retribution for defending yourself and Constantly revive you or come after you, while they threaten you,to the point that you have to log of the server then,this has happened to me on console.
https://forums.daybreakgames.com/ps...eport-planetside-2-teamkillers-on-ps4.250026/

Kill me once, I'll kill you twice.