There are posts that are launched in the library that I refuse to avoid misleading the bulk of visitors. As Roberto states, some codes are there only to educate people on how to program. I think that over time, we have managed to educate apprentice programmers on the harms of over-optimization and on the advantages of IS and OOS tests; this necessarily implies a drop in the sharing of non robust strategies, certainly less rewarding for the amount of posts in the library I agree 🙂

Regarding the advantages and disadvantages of sharing strategies or not, I think that when you think about it, the advantages outweigh the disadvantages. Feeding on the ideas of others makes us irremediably advance and also propels us more quickly towards states of consciousness with respect to our work that we will not have had by staying alone in our cellar with our code and our backtests.