Stock exchanges only halt trading in very limited circumstances. If you're referring to the GME debacle no stock exchange forced Robinhood to halt trading; that was entirely on the broker.

I won't attempt to defend Rep. Pelosi but what she is doing isn't insider trading. She isn't an insider for any corporation that she and her husband traded on. Instead she is using political power to manipulate stock prices from the outside. This type of naked corruption should be banned, but let's not confuse the issue with inaccurate labels.