The term in the context of propaganda is as clear as it gets though, if you mean to say "infecting or enabling otherwise 'sane' people with 'undesirable' ideas

The term in the context of propaganda is as clear as it gets though, if you mean to say "infecting or enabling otherwise 'sane' people with 'undesirable' ideas and behaviors". Toxic is subtext that directly speaks to people (Chinese) wondering "what should I do?" => don't use it, don't even approach it or look at it (it's toxic). It's idiomatic and quite explicit, in subtext, in this context (Chinese gov stuff).