He's probably referring to this old article - http://aegis.sourceforge.net/auug97.pdf which suggests that recursive make is bad because it can cause a lot of unnecessary processing even if you only changed one or two files. I think this just comes down to how you're using make - for me recursive make works just fine because I tend to run the specific target I need while I'm working (as it's usually in my cwd anyway) and only run the root `make all` on deployment.