I think this attitude is a little cavalier.
I've been through this argument several times in various communities. In my view, it boils down to this:
The more people that know, the higher the risk that it'll be fixed quickly.
The US Mint is a good example. Once that method got national attention, it was fixed within weeks and now can't be used.In my experience, the most prudent approach is to work on a barter type of system. The focus should be on trading information, not giving it away for free. That way you get out of it what you put in. The more research and investigation you do, the more valuable your knowledge becomes and the more you can leverage that knowledge to trade with others.
There will always be folks that want everyone to share information. Sometimes these are beginners who don't have any secrets of their own and are trying to learn. Sometimes it's folks that have a certain ideology about giving back to their community. Sometimes there are folks who haven't thought through the long-term consequences of their actions. Sometimes it's folks that stand to profit from sharing the information i.e. bloggers.
Either way, they are frequently the most vocal ones on the forums and it makes sense to be vocal. If you have very few secrets of your own or you benefit from sharing those secrets then it's in your best interest to try and get everyone else to tell you theirs.
However, it's not in the best interest of the community to widely share information in the long run. If everything was shared quickly and widely then everything would be fixed quickly and no one would be able to gain much benefit.
If, however, you focus on research and trading information then those who put in the time and effort to discover these methods are primarily the ones who benefit from them. This seems to be a much more sustainable model to me.
My two cents.