It looks strange when people on the forum seem to have so much inside information ("They all do it") but as no instances of prosecution occur, where does this information come from?
As the article states, Ron Geffner... emphasized caution before jumping to conclusions... he added that it’s important to determine the full context of the transaction. “Before public opinion judges Pelosi unfairly, it is important to determine who engaged in the transaction on her behalf as well as whether it was part of a broader change of her portfolio.”
Someone who trades regularly will often make a trade months before something happens. This isn't unusual.