Here's my two cents:
The WG stole some important stuff from Hachinosu, that only Rocks would care about.
BUT, some horny Celestial Dragon fuck-asses also wanted to bang Shakky, so they stole Shakky.
Normally, Hachinosu/Roger wouldn't give a shit Rocks had his shit taken: based on how people talk about Rocks, they'd probably be glad he got embarrassed/fucked over.
BUT, if Rocks had HIS TREASURE stolen by the WG, and THEN the WG stole Shakky, too:
Rocks + Hachinosu + Roger + Everyone who wants Shakky would show up.
The WG should have just stolen Rocks' treasures, but got greedy and took Shakky too
If it was just Rocks' treasure, Roger wouldn't have shown up.