The OP was responding to "government run Facebook?" and the premise is "we need Facebook-style technology to do XYZ things like plan events" but for-profit Facebook fills that need with these negative repercussions: "collecting, profiling, and selling to data brokers, and influence to foreign countries or private interests." and then argues that it follows that a government run Facebook should exist to handle the things that the OP is asserting are necessary without any of the identified downside.
The flaw in the premise is that you need Facebook or a government fun Facebook to do any of the things the OP suggested. You don't. And I'd argue not only should we not have a government fun Facebook, we shouldn't have Facebook or other social media to begin with.
I'm sure the OP is going to come in now and say that wasn't their premise. I'm simply responding to the words that they wrote. No matter how it is framed or how the goalposts are moved, you simply do not need Facebook nor do you need a government run Facebook.