I mean anyone that thought Warren Buffett was purely altruistic was a rube. Well illustrated with his maneuvers during the Great Recession and during the Obama years.
That being said this is fairly meh. It was a dumb company policy anyways- I think it would have made more sense for his personal investing to be aligned with Berkshire rather than segregated, as you could argue it would be ironically a conflict of interest. Also this is pretty thin- it just shows a few sales.
None of this is illegal (at least with the information available), it just violated his own internal policy. Though he reprimanded a previous employee for this behaviour, so it makes him look hypocritical at the very least.