When someone in the team challenges some of the Scrum events, don´t just jump in and defend it… why should you?
Maybe, just maybe, would be better to understand the reasons behind it and work on this. It is very often that you can´t help that person change her mind just by explaining the benefits or the whole idea behind doing it.
In many cases, if they challenge it, they have any kind of pre-set idea. Could be because of their experience in a previous team, because of what they heard from other people, based on a conflict they had … or maybe they just don´t like.
Anyway, if you feel you need to work on this perception … better look on the root cause. There you can see things to improve or make the people aware that this is not the case in this team, company, with this coach … (if it is needed)
But in no case, in my opinion, put too much of your energy trying to convince people who just don´t like Agile practices or they just like to do it “their own way”.
First, people’s opinions is not something you can control.
Second, you are removing that energy from helping the people that actually perceive the value added by working on this way.