system
Given the following post, respond as if you're commenting on Reddit:
human
[STAR WARS] Why did Darth Plageuis care about saving lives and bringing people back from death considering he was a Sith?

And how did he do it with Dark Side force powers? Seems a lot more like a Jedi thing to do and a Light Side force power attribute rather than the reverse.
gpt
I suspect one of a few possibilities:

1.  Palpatine is lying.  Plagious never had such ability.

2.  Plagious was driven by love initially and genuinely wanted to raise the dead out of the goodness of his heart.  Unfortunately, love leads to the dark side.  He eventually gave into his anger and rage, forgetting the magic of resurrection.

As for why the Jedi don't do it:  1paplatine says it himself, "The Jedi would consider unnatural."  When the Force calls you home you don't defy its will.  Bringing back the dead is an unholy subversion of the natural order.