Does it mean we can directly print any thread and all the replies it contains?
Personally, I think it depends on the situation. If the discussion is public and not sensitive in nature, then I don't see anything wrong with printing it out for personal use. It can be helpful to have a physical copy of a discussion, especially if it contains valuable information that you may need to reference later.
For example, I often print out threads related to my work, or research for a project, that I find particularly informative or useful. This helps me to have a record of the discussion that I can refer back to in the future, even if the thread is later deleted or becomes difficult to find online.