It wouldn’t surprise me if they were the ones who splashed it.
The Malaysians are BSing about something. None of it makes sense.
I doubt the Chinese “splashed” the plane.
If it was a terrorist attack it was probably directed against the PRC which has been sticking it’s bridge-less nose into everyone’s business in that part of the world. China basically claims any speck of land in South East Asia where any Chinese sailor went 1000 years ago. The Chinese are not well liked in the region.
I have been telling my Chinese friends that they should get ready for the Anti-Chinesism blow back of their actions that are going to replace that old standby Anti-Americanism