

I suspect that a large part of the problem is a combination of hearing loss and a lack of subconscious awareness of their phone. In both cases (and especially combined), they would likely not even hear the notification if it was at a volume you or I would consider reasonable. So, from their perspective, it is quiet. Any quieter and it would be too quiet to notice.
Of course, anyone capable of basic empathy would also realise that such a perspective is their subjective experience of the world and simply turn the volume off/down until later to avoid annoying other people. Sadly, many of their ilk seem to have forgotten the lessons they taught us as kids.
It’s a tough call to make, isn’t it? Baring a candidate is inherently undemocratic, surely in a perfect democracy any candidate who is receiving votes should be considered. However given the current state of global politics, it’s also equally true that any candidate who is being manipulated by an outside government (such as allegedly Russia/USA in this example) should be restricted for the very same reasoning of allowing the voters to have their say without interference or manipulation by people who have an interest in the election being decided undemocraticly.
Ultimately, the decision to prevent any candidate, popular or not, is one that should not be taken lightly. And yet must also be a decision that can and should be made under the right conditions to protect the democratic nature of elections.
I sincerely hope that the people who made the decision in this case explain their reasoning publicly, and have a very good justification for doing so.