Bold, intriguing idea. One milder spin on it could be that Obi-Wan sincerely thinks Anakin killed the younglings because he finds the bodies with lightsaber wounds (inflicted by Sidious himself), then finds the hologram of Sidious telling Anakin to “bring peace to the Empire” (maybe with the implication being the Jedi bugged the Chancellor’s office, further highlighting how morally-compromised the Order has become), and draws an understandable but erroneous conclusion with disastrous consequences.