Problem with Jack Ruby killing LHO is that he is neither a “hero” nor a police officer, he’s clearly a “bad guy” (criminal) and the conspiracy’s last desperate choice (Plan C) to silence their patsy LHO before giving away everything. He has been helping the conspiracy all along, which didn’t want a frontal head shot to kill JFK or a live patsy. We have a man throwing his sordid life away for no apparent reason. The public’s suspicions of a larger conspiracy are NOT quelled.
Think about it. If the conspiracy plan had gone as scheduled (Phase I ambush killing JFK with rear-only shots), LHO would have been murdered while resisting arrest in the TSBD (Plan A). Failing that, a limousine stop by inside man Greer followed by frontal head shots (Plan B) murders JFK but now a post-mortem cover-up requires a body double. When Officer Tippit picks LHO up and takes him to a rendezvous spot (Texas Theatre?), BOTH of them would be slain and made to look like they killed each other. Tippit was having an adulterous affair and could have been blackmailed into picking up LHO and taking him to a location, he certainly was afraid for his life that day. Tippit honked his horn for LHO at his boarding house to be able to say he nominally complied with instructions (he knew he was being set up) but later found to his horror two killers, not sympathetic-to-his-feeble-attempt-to-comply blackmailers waiting for him at the rendezvous point.