I can personally attest otherwise. There are many like this, and many of those aren't even open to building a real relationship with their recruitees, but that seems to become apparent pretty quickly when trying to establish a friendly relationship. I have found that I get better placements and better rates of follow-up interview rounds with the ones I do have a stronger connection with, which is why I mention this. You don't have to send them Christmas cards or anything - just name and number/email of the ones you didn't hate, and maybe a star next to the ones you got along really well with :)