He's not conspiring to trick people per se but he's also not being super clear. His position obviously makes it difficult to answer this question. It's possible he really believes this is better but if he didn't he wouldn't exactly tell us something that makes him and his previous employer look bad. Also his belief here may or may not be correct.

Is it a coincidence that the technical stance changed at the same time when part shortages meant that cars could not be built and shipped because of shortages of radars?

More likely there was some brainstorming as a result of the shortages and the decision was made at that point to pursue an idea of removing the additional sensors and shipping vehicles without those. This external constraint makes believing the claims that this is actually all around better, while hearing some reports of increases in ghost braking (anecdotes) a little difficult. Not clear if there was enough data at that time to prove this and even Andrej himself sort of acknowledges that it's worse by some small delta (but has other advantages, well shipping cars comes to mind).

So yes, sensors have to be fused, it's complicated, it's not clear what the best combination of sensors is, the software might be larger with more moving parts, the ML model might not fit, a larger team is hard to manager, entropy - whatever. Still seems suspicious. Not sure what Tesla can do at this point to erase that, they can say whatever they want, we have no way of validating that.