i argue that most ideas aren't necessary novel, so stealing idea isn't necessary bad.... e.g. i don't think google search was entirely novel, but was well executed.
honestly - meta has built quite a lot of cool things, but c-suite is probably to be blamed for what's going on today.
Search was not novel, but PageRank was novel.
Stealing an idea is different from lying to people in order to steal their actual business, which is more like what Zuckerberg did.