I think your judgement is very mono-focussed if I am honest. Your own experience appears to have directed the flow of traffic here (BTW congratulations on turning things around back then, fantastic work).
You mentioned the year 2000 and lack of smartphones, etc (I remember

). In many ways I think that would've simplified matters and left one less vulnerable to misinformation disguised as fact.
One thing specific to this march. It appeared to have the usual 'fooball team' vibe about it, that 'one of us thing. I think at least half of those people were there because they feel patronised and alienated (whether that is right or not is a matter of debate obviously). Ridicule will not
lead them to reject Reform. Continuing to point out how many grifters are using them by illustrating what said-grifters are not doing for the country and particularly them is the important work.
BTW what you are positing is not clear. Are you suggesting that most there have lost little? We have no idea. Poverty is a strange and stealthy beast. Again, I personally find these marches hard to stomach, but equally, it is up to the left to develop an educational playbook which can develop a candidate who can speak to these people and show them why all the stress points of blame Reform present with regards to immigrants are empty vessels.
It is mono focused, yes - it comes down to one central factor; being homo sapien.
The thread of the conversation started about, and continues to be, environmental factors impact on choice to attend a fascist hate march and to what level those environmental factors justify that attendance.
And because we are homo sapien we have agency, so the environmental factors are not a justification. They may be a reason that explains attendance, but they don't justify attendance. The only justification for attendance is belief in the content of the march - any other position is false, whether that be misinformation, misunderstanding, ignorance etc.
All the tools exist and are accessible to make informed choice, no matter where on the political spectrum that choice falls. (That was a lot harder in early 2000s.)
Re; loss. Loss is subjective. How much an individual is prepared to lose in the search of challenging (whether that be solidifying or changing) their opinion is what matters. Anyone attending the hate march that did things like loose a days work or missed a family event etc - that's loss. The ones that are "having a day out" to cos play, with a beer, on a sunny day, to fight a straw man - they've gained a day out and lost an opportunity to focus on the things in their power to improve their lives.
My posts haven't been about the people that will respond to being shown how much of a grifter Farage et all are. They already have the ability to see what's happening - some will change how they vote (and what happens at council level in the next two years will be very interesting), most won't; the appeal of Farage et all is nothing - and by that I mean it's a manifesto of "stop the boats" plus "fill in whatever suits you" here.
Reform in power is the only mechanism that will produce a result, because you can't argue against "the grass is always" greener if the picture of the grass only exists in the perspective you are presenting an argument to. It's arguing against a fantasy of perfection - which is impossible.
You mentioned the football crowd type vibe. I covered that in my comments about loss - social loss.
Reform will remain an anti establishment vote wilth a magic bullet until the results of their actions show otherwise, unless the current government get lucky with a global event that makes life feel better soon.
The only lever I see for a current government is wealth tax - it's a "working man" first policy, and one you can trap Farage in.
I do think the next few years will change things.
The Tories screwed things.
Starmer was a damp squib.
Whoever is next will make more noise.