Actually thinking more on the mafia thing and it's actually extremely accurate to this situation.
Do you know what the Rogues' number one rule is? The Golden Rule? The most important rule? The unbreakable rule?
The Rogues never intended to kill Bart. Their attacks wouldn't have made a dent on a skilled speedster like Bart. They didn't realize his powers were gone.
They didn't want to kill Bart.
Not out of any form of respect or admiration. No, they didn't want to kill Bart because they feared retaliation.
When they realized Bart was dead they immediately tried to murder Thad. Thad was the one who had stolen Bart's powers. He was the one who had tricked them into murdering the Flash. He had set them up to be scapegoats. They knew if they killed Thad, right then and there, they could escape some of the wrath that was about to rain down on them.
Thad escaped. The Rogues went into hiding. They had seen Wally's return. They knew what Wally had done to Thad. What he would do to them. They knew how absolutely fucked they were.
No one would let them hide with them.
They were suddenly tainted. Socially ostracized by the villain community. No one wanted to risk being associated with them. No one wanted the Flash to associate them with the Rogues.
(Sidenote: Yes. Yes, the non-stop lightning storm was the Flash)
The Rogues had a tough few months. Wally and Jay were relentless in their pursuit to track them down. No one wanted to help them out. There was a cult relentlessly trying to get them on their payroll because they were the only ones who could successfully fight a speedster.
Then they heard that Inertia had escaped.
And a golden opportunity presented itself. They could kill Inertia. They could get revenge on him for tricking them. They could send a message to the villain underworld not to fuck with them. Most importantly, they could placate the Flash. And all they had to do was break their number one rule. One. More. Time.
Thad never stood a chance.
Really, if you think about it from a mafia perspective it makes a lot of sense. They crossed the mob boss. They were forced into hiding. No one would help them out of fear of fates worse than death. They tracked down their scapegoat and delivered his body on a silver platter to get back into the mafia's good graces.