Strange, the first thing I see upon starting WC3 is Thrall leading an orcish army through a human town in clear violation of the Alliance Internment Act that was keeping the peace in the land.
And your attempt at excusing the Horde of their crimes is easily disproven by Saurfang noting that the majority of the modern Horde follow the bloody legacy of Blackhand, while Thrall and Vol'jin were the outliers.
Finally, any attempt at disconnecting the WoW Horde from the Old Horde is futile as the WoW Horde literally named their capital after the Warchief of the Old Horde. The moment Blizzard decided that the """"modern""" Horde capital should be named "Orgrimmar" is the moment your entire argumentation crumbled to dust.
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The thing is that Blizzard itself never defended Garrosh or presented him as a reasonable dude, in fact pretty much everyone immediately turned on him, as they saw that he was a genocidal lunatic, starting with Cairne and Vol'jin.
It's just a vocal minority on this forum that is adamant on defending Garrosh's and the Horde's actions in Cataclysm, even though the story never makes any attempt at doing so.