This seems to be a recurring confusion in this thread: the boring aspect is a consequence of certain other factors, it is not a reason in itself for interruption. It would be rude in my opinion to interrupt someone and change the subject because they are being boring. However, if you consider the specific examples I gave you'll see it's not about it being generically boring, it's about the speaker having a misunderstanding of the knowledge-state of their listener.

In attempt to say it with absolute clarity: interruptions that shift topic are rude and I would not advocate for them

If it wasn't clear then the redirection of the conversation would only happen after the person has come to a junction in what they are discussing.

Not mid sentance, nor mid explanation that has not reached some settled point.

There is nothing rude about directing a topic of discussion if done with tact and respect.