Yes, there are certainly a portion who are brainwashed/indoctrinated through propaganda, but I consider it more likely that universal education, and what was deemed socially-acceptable by the majority/community, were suppressing the base instincts of those who are empathetically deficient.

Now that capitalism and technology have simultaneously isolated us from our local communities, destroyed the social contract, and can deliver us sociopath-curated-propaganda and misinformation algorithmically, those people no longer feel the need to hide their terrible beliefs or personalities.

Narcissism is being made socially desirable and acceptable. It is a largely-manufactured mental illness epidemic.