Ubuntu does stand for a certain set of values; security built in and doing The Right Thing on the behalf of the end user are part of it. That does lead to certain distro semantics that I'm sure not everyone will like. And that's OK, we do appreciate that some people want to control more deeply what happens in the distro.
There is a whole other set of users that would prefer that Ubuntu kept out of their way administrative actions for which they trust the machine to handle. They are probably more silent because they are mostly OK with how things work. And I'll say that I'm not comfortable with everything about snaps so it's more of a spectrum than binary acceptance.
Snaps were invented because we had a problem. We wanted to make it easier for software publishers -- think games, desktop tools, browsers -- to deliver their software to Ubuntu users, but debs were both too hard and too powerful to make that a viable proposition. In the old days, people relied on archive.canonical.com [1] from which debs like skype were published, but it was unsustainable and led to poorly packaged and out of date software.
Regarding third parties, in the end, nobody in the community reads through the source code of every patch applied to binaries in their systems. There is a degree of assumed trust in any update. I accept that trusting Canonical is one thing and trusting third party publishers is another, but given the motivation I describe in the previous paragraph, the decision to use snaps wasn't made in a vaccuum.
[1] Which still exists, if you want to go and check out the pool for third-party binaries. All of those installed as root!