This person, must be a joy to be around in parties /sarcasm.
Whilst I agree with her sentiments that we should be real, and not act fake.
I disagree with her about too much positivity. LinkedIn is a social media platform, and it is used to show your best side to the world.
By showing faux positivity, ppl are using it to seek new opportunities, if I see ppl complaining or swearing on the platform about their former employer, I would be reluctant to hire them, because how ppl conduct themselves in a time of hardship, speaks volumes about their character.