Did you even know those users who had show their Bitcoin investment in this forum are made up stories?
Some of the stories are fake, but there is always the real story.
They're show it because they can earn easy merit from other users, but they're not have any reason to invite people to invest in Bitcoin. So if you read such thread, it's not real and you just need to avoid to read further when it's about Bitcoin investment or things he bought from Bitcoin investment.
Basically everyone who wants to invest in bitcoin must be able to account for their decisions properly. They can ask experienced users for advice, ask someone to share tips, or something else. But when it comes to investment decisions, none of this should be the reason why they invest because each of them should think of it not as financial advice.
Indeed, there are always users who are affected by other people's benefits shared around the forum or somewhere. But unfortunately, they don't do any analysis before investing their money. That was greed, definitely a mistake to be avoided.