Grounding your dish disolves static build up on LNB, bonding to existing common house ground by way of a ground block may not divert all power surges and strikes but will reroute most of them. That is what the theory that power follows the path of least resistance means. All systems should be bonded to existing common house bond, not a seperate ground, such as a 3/8'' ground rod, as that can cause a differance in potential should a nuetral fail on power side. Do not ask a dish or directv installer about bonding practices, I "may" see 1 in 30 that are bonded properly.The only thing correct in his statement is that grounding does not STOP a lightning strike, It is not there to stop it, it is there to reroute it to ground!
But to answer your question, NO, it should be included in any professional install and anyone putting their name on an install that is NOT bonded is liable for damages. Unreal that in this day and age this is still an issue to be argued!!