Why do a lot of talk show hosts, say something like "Thanks Bob for filling out for me and doing a great job"?

As if they are the manager and they got a subbordiante to replace them, and they are assesing and praising their job. Or as if they asked a colleague to replace them who agreed to do them a favor. Neither is the case. Why do they lie to themselves and to the public like that? (edit) i don’t mean it is a big big lie or anything, they just do it every time.