It's not her who's complaining, it's her mum, who might just as well be complaining about the behaviour that led to it as the sentence. I think it's OK for a mum to be disappointed that her daughter will miss her son's wedding, but not to expect that makes any difference to anyone else.
Protests that don't cause disruption have never achieved anything, there's not much point in a peaceful non disruptive protest, and there are numerous people in history who we need to be grateful to for protesting, despite the personal consequences.
I do think it's a bit much that this is the same sentence as the one handed to the child rapist in the news this week.