I’d argue that it’s because the forum is a community, so you should do what you can to make it a safe place.
If I had realized the thread was many years old, I might have thought twice. As it was, it was a link in the sig file of someone I sorta kinda recognized as being legit. I don’t think you have to scan sites like Google, but maybe a warning based on the date the link had been added to the thread would have been helpful to me.
I mean, this is from forum software that gleefully chastises for people who engage in troubleshooting after the link has been clicked. If you can do that, you ought to be able to do this.
Help a brother out. Throw me a fricken bone, dude!