You try to attribute to malice what could well be the most obvious thing to do. Killing enemy ships is important. The moment I spot a target at 20% hp - even if I see someone else clloser, easier to kill - of course I'm going to try and switch my fire to the vulnerable opponent in hopes of killing him before he manages to disengage or heal. Focusing the low-hp targets is like the basic of the basics - and sure, sometimes - depending on the situation - I can say "I don't need to shoot him, he'll be dead right away thx to other people already shooting at him". But this assessment can also turn out to be wrong. I've made this mistake before and there are few things as frustrating as seeing enemy get away because you assumed he's as good as dead... but he wasn't.
Reading KS as "kill secured" is only partially a joke - the only enemy that you can really assume dead is the one whose name is already greyed out on the player list. So yes, it's pretty common to see many people ganging up on the enemy only as he gets low hp. But attributing it to killstealing is quite immature, really. I mean, sure, there happen people who just want to accumulate the red ribbons, but even if there was literally no reward (even cosmetic) for the killing blow, low hp enemies would still be the priority target.
A ship with 50HP can still unleash deadly salvos on your team, secure that kill!
There is a difference between killing the enemy which is running away, and holding fire like FOREVER to wait until one target is low enough to kill it. Then u get ppl with several kills and lucky when they are in the middle of the pack XP wise after the match....
In a time where ppl think service costs are still tied to damage received, dont u think ppl are deliberately killsecuring? Thats like playing totaly blindly.
Ive called ppl out for that, and after watching them more closely, they sure did that. U cant hold your fire only to shoot low targets. Look at some bad players streaming on twitch, and u see it does happen.
Either give the one who did the most damage a "kill-assist" ribbon or just give the kill ribbon straight to the one doing the most damage and the other gets the "kill-assist" Both would be fine imo, and ppl who work their buts of do deal with high health targets get some form of reward.
Don't be that guy that hold his fire, if you're reloaded and have a target - shoot!