The question the world’s scientists are tackling is to what extent human-caused global heating is to blame for a particular extreme weather event as opposed to natural variability in weather patterns.
I appreciate the author bringing up this point to acknowledge that there may be other sources which lead to the extreme weather that occurs today. It is effective in avoiding biases and also raising the question to the readers of whether there may be more than one factor which goes into the extreme weather we see today (i'm not saying I think global warming is not the cause).