Why doesn't the Left admit it's wrong?

Nigel Farage points out that Donald Trump warned the UN that German reliance on Russia for energy was a big mistake. Trump warned that it would make the Germans vulnerable to extortion and intimidation and that Germany will become totally dependent on Russian energy.
The video showed the Germans at this UN meeting, chortling away. ‘What a silly thing for Trump to say’ they appear to have thought.
Then to each other they probably said, ‘Has Donald Trump forgotten that till 1990 half our country was pretty much Russia – it was just called ‘East Germany!’
And probably laughed again.
Fast forward to 2022 and the embarrassment that is Germany’s foreign and energy policy exposed for all to see. The sound of the screeching Mercedes (or Lada) U-turn is deafening.
I expect on Day 1 of any Economics course you would learn that relying on a monopoly supplier, without a Plan B, isn’t clever. But because it was Donald Trump who told them, it was somehow OK to ignore it. Maybe even compulsory to do so?
A moron in a hurry would not have made that mistake.
So why don’t these people admit they were wrong? Why is it OK for Democrats, the legions of woke, left wing academics, people who live in Islington and those who read the Guardian or watch CNN - why is it OK for them never to give Trump credit when it’s due?
Why is it acceptable to be a bigoted prat if you are opposing Donald Trump but not if you are disagreeing with anyone else.
How did that come about?
My view is that this is the same mindless, dangerous attitude that ‘the elite’ adopted towards Nigel Farage as he campaigned to get us out of the EU. The same licence to insult and ignore simply because he (and Trump) were ‘different’. Which gets this attitude very close to that found in racism and discrimination.
It’s time that these people found some intellectual integrity, dropped their nauseating prejudice and accepted the obvious - that Donald Trump was indeed right about some things and maybe people ought to listen more.