I have to agree. We've been sticking to the guidelines pretty rigidly throughout lockdown, but when we've been out for a walk the vast majority of younger people have adhered closely to social distancing, waited patiently to pass where the pavement narrows, politely acknowledged when you've done the same etc.
It's the older people who've barged past, not waited, not kept a distance when it's more than possible to do so and generally been quite rude. Not all of them of course, but disproportionately more older people don't seem to give a toss.
My experience has been the exact opposite of yours