I'm a big fan of the UK and its rich cultural history. I worry about it losing itself by way of PC and the kind of self-loathing espoused by leftist elites. You can and should be proud of who you are as a country.
I can only agree with you indeed I would go further and suggest that the rich diversity of debate is being drowned out by the heckler. There are numerous cases in the UK where plays and cultural events have been abandoned and cancelled because they have inflamed the ire of some small group of hecklers advancing their own interpretation of "alarm or distress" or "racial hatred" (as per your posting of the disorder act above). How does one interpret these terms? The law's intention is to provide protection from "distress" which may be a crime under the act as opposed to "offense" which may not be.
I am not a great fan of social media (especially for "political" purposes) in fact I hate the concept of it with a passion because of the impact it can have on people, their lives and their reputations. Social media like chat forums are a natural home for the heckler and the extremist. They can babble their message no matter how offensive or stupid and that message can then be passed on and on; the more it is transmitted the more it is read the more febrile the reactions become. The Trump re-tweets being a case in point, they have become a rallying cry for the extremeist.
For me its not about being PC or whatever your interpretation of that is, its the legitamisation of the heckler and the extremeist. For me Trump embodies this manifestation by not only his words but actions as well, he is becoming an incubator for extremism in order to further his political agenda at the cost of the rich diversity of debate.