If we hypothetically assume this is true for a moment, then consider:

1. No SAMs would have been fired if there were no Russian missiles attacking Odesa, and thus indirectly it's still Russia's fault.

2. The Russian-designed and manufactured S-300 (and presumably the closely-related S-400) are dangerous to use over populated areas if they have no working safe abort or engagement minimums safety features, therefore they are even more dogshit than we thought they were. So, Russia is still at fault here for supplying unsafe SAMs, and no-one should buy any Russian SAMs in future if they care at all about their civilian population. If we assume that the anonymous Twitter source is indeed correct, then this is probably why Russia isn't saying anything about it.

I'm sure once the war is over we'll get some proper analysis from people with actual warhead ballistics knowledge though, and not just some anonymous propaganda.