In my mind the simplest explanation is not something nefarious by Google, but simply that advertisers don't want to be associated with controversial videos.
Then why would the re-monetization and restorations happen? It makes more sense that the timing of denial is the key thing. Also, it's an article of faith for implementers of large systems, that if something can be exploited, it will be exploited. This applies as much to attention and political power as it does to monetary gain. In the case of the 1st two, the exploitation is probably done by low level employees for outside interests.