I think I finally understand.
Plastic bags and global warming are off topic, Describing why they are off topic is on topic.If I disagree with you it is off topic.
If I agree with you, it is on topic. If you agree with me, it is really really on topic. And poking fun at inconsistencies is really really really off topic. And as ever Do as I say, not as I do, is the Golden Rule thanks all. Nancy