The writer is addressing annoying behaviors. Of course if you're hired with any experience at all, you're expected to bring prior knowlede to your position. I believe what's being referred to is an individual who continually refers to the practices of a previous workplace as some sort of ideal benchmark, even when there's no problem being presented to them or solution solicited.
I don't think the implications was to not share ideas learned, just don't annoy people with endless descriptions of how things were done at 'XYZ'. I know personally it makes me think "Gee if things were so great at XYZ, why don't you go back there"