Yeah but it essentially made the other Samurai Jack episodes pointless. Why bother being nice to some kid in the future when you're going to remove him from existance?
Scottsman? Gone. Archers? Gone. Woolies, JumpGood, the Scientists, the Sea Men, robot-citizens, LuLu, the Farting Dragon, the Japanese Mechanic Family, the SAMOOHRAI, the Baby, the Bounty Hunters and Princess, Imakandi, Moth Prince/Princess, X-49, the Spartans, the Ravers, that Totoro-Monster Thing, the Dogs, that Lupin the Third cameo, and many many many more are all WORSE than killed.
They are wiped from existence. They gave their lives to defeat Aku and make a better world. HOWEVER, what they did was, to them, morally and logically WORSE than anything Aku had done to them. Their timelines, their lives, their experiences, their familiar and loved ones were all utterly destroyed. They'd do LESS damage if they just destroyed their own planet along with Aku.
The show built up he couldn't go back to the past. They should've gone with "Yeah, shit happens. But now it's time to make shit good again. We can't go back to the past, but we can make a future."
I feel like they were actually going for this, but last second someone was all "FANS GET SUPER MAD, QUICK MAKE ASHI HAVE TIMETRAVEL POWERS"