Sure, but there's a small theoretical difference with democracy. You have to live under some system of government. You don't
have to use a secure messenger. You can choose to have sensitive conversations in person or not have them at all.
I agree that in practice, a lot of people are going to use their phones for relatively sensitive conversations, and in practice, Signal remains the best choice for doing so. But there are a few real threat models where the options aren't Signal vs. SMS / Google Chat / Discord / etc., the options are Signal vs. nothing. For instance, you could be a journalist deciding whether to ask clarifying questions to a government whistleblower via Signal or meet up with them in a park. You could be an activist/demonstrator under a repressive regime deciding whether to coordinate some action this weekend via Signal or hold off on it entirely and tactically preserve your freedom. And so forth.
For those people, if (and to be clear this is a big "if," while this issue is one serious piece of evidence it is nonetheless inconclusive) Signal isn't trustworthy, it doesn't matter if Signal is the least-bad of the options.
(Also, it's not like Signal is the only e2e messenger around. There's iMessage/FaceTime, for instance. Churchill's claim was that the abstract idea of democracy was good, not that any concrete implementation like the British government was good.)