I can think of several possibilities:
1. He’s super dirty and the insider trading is the LEAST of his crimes. But it’s the public one that he’s allowed to use to cover up the rest.
2. It’s a warning to other dirty Rs that this will no longer be tolerated.
3. He’s being taken out because he’s not with the anti-Swamp program.
4. He’s being taken out in order to introduce evidence in his trial. (Q keeps mentioning things about “how do you introduce evidence”)
5. He’s a vulnerable R seat and needs to be removed now in order to make way for a more solid R on election day.
6. They all do insider trading, but perhaps there are agreed upon bounds and he exceeded them.
7. Maybe he backstabbed the wrong person.
Probably other possibilities as well. Those above are not all mutually exclusive.
All very good possibilities.
Perhaps more than one scenario applies.

Let's remember what Q said about Maxine Waters, Diane Feinstein, Adam Schiff, Nancy Pelosi, and others. They are dirty, and there are many others who are dirty.
What if Session's DOJ just arrested and indicted a Democrat member of Congress this morning, instead of a Republican?
Can you imagine the outrage in the media?
Probably other possibilities as well. Those above are not all mutually exclusive. If you were running things at Trump's White House, would you lower the boom first on a fellow Republican that you knew was dirty, before you lowered the collective boom on many Democrats?
I sure would.

#6 is my favorite, but all the others are possibilities.
I just realized I had missed generally’s points that you were quoting, Sky. My apologies for the mixup. You BOTH analyzed this very well..... and I really liked the pix you posted with it, Sky.
What a lovely piece of leverage to have on ALL of them.
Isn't politics fun? Trump/Q know how to play. Not bad for a guy into year three of politics, yes?
#AlCaponeTaxEvasion
Bagster