"How constructive this remark is."
Indeed, it is, thanks.
"warn the writer about the errors, so he can correct?"
I thought I did - with these comments. I'm hardly in a position to correct them _before_ he publishes, am I?
If I were to correct all the errors in the article, it would take a long long time, and be substantial. It's not worth my time - there's already far better and far more accurate information on OpenWrt - on its Wiki.
If it were only a couple of minor errors, it would be different. But you cannot excuse these glaring errors by saying it's "not constructive".