a lot of people are adding Reported to be stickied
to the end of their replies and I dont know why

Usually this statement means that someone has reported the first post, and in the text box explaining why they reported it, they explained they wanted the ST to sticky the topic for some reason.

It means that they think that the topic is good enough to be a sticky post, meaning it is a good guide and should be seen by many people.

The sticky topics are the ones pinned to the top of each forum category. They are sticky in the sense that they are stuck to the top of the topic list and don't fall to the next pages, unlike ordinary topics that are sorted by recent posts.

Only the scratch team can pin topics. Users who think a topic should be pinned will have to ask the ST, reporting a topic and asking is the main way this happens.