You're asking questions of concern without taking a side by the way, suggesting that maybe the mainlanders are right to see the protesters as violent and deserving of violent repression by a dictatorship. I would urge you to be a little less willing to take the dictator's side on this.
The mainstream media were all, in orchestrated unison, arguing loudly for the war. And the government provided lots of allusions to evidence and appeals to authority, demanding support for it. And this was a conflict with the 'good guys' versus a literal dictator who was undoubtedly a horrible person. Yet the consequences of that war far dwarfed the atrocities of that man. And it was all based on lies. There was no WMD, the secret high level insider source was a taxi driver who had no connection to the government, the 'mobile weapon labs' were helium generating stations for use in conventional artillery, etc.
Throughout history it's not infrequent that such things happen. We'd like to imagine that when the 'good guys' win good things happen, but reality is often not so kind.
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Attaching this as an addendum since I've now been throttled for getting downvoted:
I am referring to things such as the single word title piece ran by the Washington Post, "Irrefutable." [1] On the same day the New York Times published this [2] piece entitled "Irrefutable and Undeniable". And there were many other such pieces being run as well. It's just a tad tedious to dig up these articles now from 16 years ago. It was bad. Note in these articles the complete and absolute lack of any sort of critique or even consideration of the possibility that evidence might not hold up to scrutiny. Instead the media condemned and proclaimed with absolute certainty. That was not, is not, journalism - it is propaganda.
Consequently I find it important to always remain critical of anything that has substantial political undertones. And so I prefer to take information that both sides agree to and judge it for myself while giving the arguments a distant secondary interest. And while it may ultimately leave me drawing the wrong conclusion, I'd rather be able to justify my logic based on evidence I personally felt compelling beyond any doubt, rather than on parroting others' analysis.
I don't really understand why more people don't think this way.
[1] - https://www.washingtonpost.com/archive/opinions/2003/02/06/i...
[2] - https://www.nytimes.com/2003/02/06/opinion/irrefutable-and-u...
It was one of, if not THE most divisive and unpopular decision(s) the Blair government made, even at the time.