What's meant here by "[the heresies] are actually unconscious?

Question

In "The Crime of The Communist" by G. K. Chesterton, there is a conversation between many persons about the communism:

‘Well, you’re all very down on Communism, of course,’ said the Master, with a sigh. ‘But do you really think there’s so much of it to be down on? Are any of your heresies really big enough to be dangerous?’

‘I think they have grown so big,’ said Father Brown gravely, ‘that in some circles they are already taken for granted. They are actually unconscious. That is, without conscience.’

I don't get the whole meaning of this two quotes, especially the bolded phrases?

Does the first phrase mean "there’s so much of it that deserve to be down on"?

And the second one mean "They are actually unconscious. That is, without conscience"?

Answer 1

"there’s so much of it that deserve to be down on"

The Master is trying to indicate that Communism is not nearly as prevalent or as dangerous as they think. They're taking what is a minor issue, that the tendency of young students to profess an admiration for Socialism or Communism isn't some indicator that there's a great movement that must be fought.

"They are actually unconscious. That is, without conscience."

Father Brown is indicating that the ideas have become so prevalent that people don't even stop to think if they are right or wrong. He is making kind of a etymological pun in that "unconscious", or without thinking, comes from the same root as "conscience", in that both are about being aware, although the former is a general lack of awareness (being unconscious) and the latter is a matter of not stopping to think, and thus not being aware, "without conscience".

I believe that Father Brown is less directly condemning communism (although, in his time period, it would have been a common view), and more condemning people accepting and espousing ideas without actually critically thinking about them.