I'm never sure why people think you have to be 'brave' to join in political discussions - no point of view is more important than another. I find that having to defend my point of view makes me think about why I hold it, and I can modify it if I learn something new.
I agree with the article about context, though. Offline, when we listen to someone, we know where their expertise lies, and can judge their opinion accordingly. Online, there is no way of telling whether someone knows about the topic under discussion or not, and a lot of people insist that their opinion is as relevant as that of an expert, which can make for a lot of pointless discussions and misinformation. A virologist can explain why she thinks something about Covid, for instance, and then someone with no training in virology will come along and say 'That's rubbish! in my opinion . . .'
I don't think the article was referring to sites like this, though. It was more about Twitter and similar unmoderated 'anything goes' places. There are so many rules here that I don't think that the communication is natural at all.