There's a long and distinguished history of thinking your enemies tech is better than it is. See wehraboos and tankies.

In all fairness though, if your enemies are just Afghan tribemen of Vietnamese farmers with an AK you don't have much of an excuse for losing. But even then you can can the moral high ground because you value life more than them.

Yes, it's all propaganda. But they are distinct tools (approaches?). It's fine to say your enemy has better equipment though, because that gives you an excuse for more R&D and gives you an excuse if you didn't win, why the win took longer, why the win was 'honourable' despite the win seeming inevitable by every conventional metric.

To be slightly more kind. I suppose you could argue this helps the peace afterwards.

If you say the beaten adversary was a worthy opponent, they can help keep their heads high. The Allies are now friends with Germany and Japan. I'm sure some reframing comes along with that.