It's the opposite of shade, unless GP is being sarcastic. "Class act" is normally a compliment, and in the context here it sounds to me like they're congratulating Baidu/the researchers in being transparent about where their ideas came from.
Any compliment can be repurposed as sarcasm, but it's obscenely cynical to immediately assume a compliment is sarcastic - instead of just a compliment. And by the way, there's no 'real' in the poster's message.
Cheers.