I'm not going to ban you because I don't want to give the impression that there's anything personal about this (there isn't), but please don't assume that these requests have no teeth.
> I can't even fathom how someone could convincingly argue that. And honestly that makes this whole post kind of ridiculous to me
This might depend on their definition of "peace". If they - very much tautologically - define "peace" as "Everyone is living in accordance with Islamic law." then according to that definition Islamic law certainly is a perfect recipe for peace.
That'd just not be the usual understanding of peace.
https://www.timesofisrael.com/museum-acquires-bertrand-russe...
In modern western society, adultery, one of the worse possible civilization destroying crimes, is hardly even regarded as truly evil and is glorified in media. Especially when women do it.
So you mean that to you it's so obvious that shariah leads to peace that you have trouble understanding how someone might disagree? Then I assume that you completely agree with all aspects of shariah, right? Then why would achieving peace require killing homosexuals and apostates? Are those two specific groups particularly violent? It seems to me that killing is quite a violent act, so homosexuals and apostates would have to be really violent to justify outright killing them.