When people are silenced for expressing their ideas for whomever will listen, that is abuse of power.
I do not find what you have written above to be completely unreasonable. It sounds reasonable at first, especially because you have confined the domain to "ideas" and people willing to listen to those ideas. I think it makes sense to treat this as a proposition and search for counter-examples. Could any ideas be harmful? Let's suppose the idea is to commit an act of violence and the persons willing to listen are in a secret room engaging in a conspiracy. I wouldn't call it an abuse of power if there are laws enacted against such conspiracies.
If someone is purposefully trying to do or post something at the expense of others or to cause a disruption, they should be stopped.
Well, here, I think you are addressing the exceptions to the proposition. If the person expressing the idea is doing so in a harmful way, then they ought to be censored.
BUT what about exceptions again? So, how about if a comedian makes Donald Trump the butt of a joke. Then, they are "purposefully trying to do something at the expense of others," but we would still allow it because it's freedom, right? So they shouldn't be stopped?
I think there ought to be a distinction between different kinds of harms, such as physical harm and mental harm. Now mental harm can be very narrow, it can just be that someone is offended by someone expressing themselves.
When we talk about political free speech, though, one of the reasons for it is so that we as a society have a free marketplace of ideas. We want to have ideas out there, authentic ideas, and as we know opinions are like assholes; everyone has one. So one person's idea is another person's offense. If we then want to have a free marketplace of ideas to make progress as a society, we ought not to censor (at least by law) ideas that someone may find offensive.
Whether the idea or expression generates ADDITIONAL harm, either physical or mental, is a DIFFERENT question.
Within this category I'd include child porn of a real individual abused and retraumatized by spread of such imagery.
How about a person who knowingly tries to induce a seizure by presenting an epileptic with a deliberately flashing image?
There are additionally other expressive things outside the scope of a free marketplace of ideas and expression such as inauthentic speech or images that materially harm another's reputation and/or income with deliberate intent, or false advertising which is another form of inauthentic speech in order to reap benefits by essentially tricking another (harm).
