Triggers and managing shared space

Sometimes real life events gets in the way of posting it may be that you're going to be away, you have bigger priorities at that moment  or and this does happen to me from time to time, there are things that bring back painful memories  that can  completely override your emotional sense that you are locked in that emotion.
Such 'Triggering' is very much for real where some item, topic, or event has an effect like a Trigger that causes you exhibit that behaviour and you may not realize it until minutes later just how it's effected you.
It's not that you don't like to see something or a group of people to discuss a certain topic or other to the point you really wish to prevent or shut down a discussion you don't agree with, which sadly sometimes people like me can be accused of.
Most of us accept you can't and wouldn't wish to prevent others exercising their rights to 'free speech' but rather where it's the case you know certain subjects do have an effect and you're in a space be it say in cafe or in a online chat room connected to a site that's not about the topic, is there anything wrong with recognizing it and not talking say around things like guns, forced sex and so on?
Are these topics that might in any event be better discussed by those with an interest elsewhere?
Is the appropriate response to a polite request to change the topic "It's my goddam right to free speech and I'll talk about what the hell I like here" or is it not the case while free speech as an excellent ideal, worth upholding it too is subject to some qualifications and even a degree of recognizing what you may have a perfect right to do doesn't necessary make it right to deploy it in each and every situation?
How hard is for to create spaces wherere most of us can feel 'safe' in?
It's also why I'm so loath to use online chatrooms where too many times people feel so detached from another emotionally, they refuse to even consider anyone elses needs.