One was moved to the Trash because you didn't post enough videos to start a new thread. When that happens, you can continue to add videos and when you have enough, you can request to have the thread moved back.
A second was moved due to the title. Titles should always tell people what sort of material is in the thread. And if that full movie post was in one of the single movie threads, then the title needs to include the name of the movie and the year of release. Those sections all have additional and specific rules.
The third one had screenshots that violated the rules because they either only had one image in it or multiple preview generating programs were used. The reason for that rule is primarily to prevent people from 'stealing' other people's screenshots. When that does happen, those people tend to complain a lot.
People sometimes think it's too harsh to Trash a thread over rule violations. But when you leave a message in the thread asking them to correct the violation, more often than not they either don't see the message or just plain ignore it. Even when you PM them about it, people choose to ignore those messages as well. But when you move their thread to the Trash, that always gets their attention!
Remember, even when a thread has been Trashed, it can still be fixed and moved back.