Rarely. In a few instances, the courts have upheld compelled speech in the commercial context, where the government shows that the compelled statements convey important truthful information to consumers. For example, warnings on cigarette packs are a form of compelled commercial speech that have sometimes been upheld, and sometimes struck down, depending on whether the government shows there is a rational basis for the warning.
Have courts upheld compelled false speech?
No, and the cases on compelled speech have tended to rely on truth as a minimum requirement. For example, Planned Parenthood challenged a requirement that physicians tell patients seeking abortions of an increased risk of suicidal ideation. The court found that Planned Parenthood did not meet its burden of showing that the disclosure was untruthful, misleading, or not relevant to the patient’s decision to have an abortion.
Also: 1) don't completely block the tweet, just have it not show up the the recipient or the recipient's followers, 2) do this quietly, so the sender isn't aware of it thus receives no feedback to use to try to get around the recipient's personalized filters.
No self defense against women by men? Yeah, bullshit. I haven't watched the video of the incident in question, so I don't know what he did in this particular instance was justified, but as a general principle it's absolutely fine.
This is a secret interpretation of what the government is allowed to do. There hasn't (yet) been any (documented) instances of secret interpretations of laws about what private citizens are prohibited from doing.
Citing security reasons, the U.S. has intervened in routine state public records cases and criminal trials regarding use of the technology.
The linked article didn't have much details on this. Did a defense attorney attempt to challenge the use of the cell tower spoofer, but to do so would need details about the spoofer, and the DA refused to hand over the info on grounds of national security?
Now I'm not trying to lay the blame for this at the feet of the Slender Man phenomenon, but there is a big difference between things like video games and Dungeons & Dragons vs Slender Man, which is that the former are games to be played, while with Slender Man a lot of it is non-game content presented as if it was real. If you're playing a game then what you're playing can't be real, as you're in the middle of playing it, so you'd have to be really delusional to think it's real. But with Slender blogs and vlogs, since they're not something being played, a person doesn't need to be nearly as delusional to think they're real.
Of course, if these two girls actually believe what they're saying, in addition to being delusional, they're sociopathic enough to not only be willing to commit human sacrifice, but they also want to be the servants of an eldritch abomination. With a pair of delusional sociopaths like that, it would only have been a matter of time before they ended up doing something horrible.