Couldn’t disagree more, not good advice I’m afraid.

Being open and honest with your friends can be greatly beneficial for the relationship, and your/their mental health. Obviously if you go around saying how much you hate them, then you’re mostly going to get a certain kind of advice, or maybe somebody will disagree with you and highlight a failing of yours, or help you realise you, in fact, don’t want to be with them (and that’s ok).

My ex would’ve benefitted a great deal from being open and honest with their friends about our relationship, primarily because they were being deeply unreasonable & we would often find it difficult to constructively disagree. I frequently wonder how different it would’ve been if they’d got some perspective on their own behaviour.

Communication is everything, and talking through your thoughts with somebody that’s not directly involved but can sympathise with your perspective can help you immeasurably.

Of course there is a flip side, maybe your chosen confidant isn’t very emotionally mature, or maybe they don’t care enough to really try to listen/help…in which case I would potentially try to find somebody more suited.