This is an assumption unsupported by the data or this website.
We do not have accurate position details, nor exact dates and times for the trades, to understand their earnings. Further, Congress members only provide ranges of values for the trades they make, with a significant reporting delay.
So, yes.. if a Congress member passed along material information to someone that they traded on, both should get prosecuted. I'm not sure I've seen it happen to politicians in my lifetime, but totally should.
Nancy Pelosi's (net worth $112m) recent financial activities with Emhoff make me very dubious about this.
https://fortune.com/2021/07/08/house-speaker-nancy-pelosi-hu...
etc etc
Significant portions of that are due to her being married to a venture capitalist and real estate investor.
Separately I mixed up Paul Pelosi with Emhoff, Kamala Harris's current husband.
That being said as far as I know it is only trades they make so there may be ways around it but just an interesting point of data.