How is he a tool for undermining the proliferation of facts? Just because facts come from a sexual predator doesn't make them any less true. If someone isn't willing to put in the effort to validate truth, then they can't handle it.
I think they meant a tool for the government (in the sense that they can use him as an example to pass laws limiting press freedom or to punish him to dissuade others).
Also the sexual crimes related to Assange (regardless of whether you think they're true or not) are allegations.
