Saying "You all deserve to be here" isn't intended as a pat on the back to the privileged in the audience, it's a reassurance to the ones on full financial aid and looking around and feeling out of place among their wealthier classmates, or the minorities who are worried that they're only there at all because of affirmative action.
Yeah, this. It's good to help incoming students realize two things.
1. Half of the class will be below average. Deal with it.
2. Everyone is capable of doing the work with enough effort.
I had a guy in one of my first year grad classes at MIT who literally passed out during the first exam from not having slept due to stress for days. Poor guy. I was already used to failing all the time, but not everyone gets that in university =/
Whilst not necessarily relevant to the main thread: I absolutely agree with you on the point of understanding that you aren't going to be the best at everything, or even anything, necessarily.
The earlier people have that realisation that its not necessarily about being the best, so much as it is about trying to be the best, the sooner they overcome any sense of impostor syndrome.
At least that's how I read it.