Wondering what he thought would be him doing "a better job weighing in"? It seems like his deleted tweets were apparently too honest? i.e. in arguing that there was no data breach, he argued that FB's API and TOS allowed (without oversight) for all app developers to do the kind of data harvesting Cambridge Analytics did? That was well-known by developers, but I guess it's different stating it as an official policy.
And probably the legal department too. He was inadvertently delivering ammunition to anyone who might want to come after the company for this, which seems like something that might very well happen.