I don't feel like this. I voted Remain, but to be honest, not with any great gusto, or with any sense of superior knowledge. I didn't understand many of the issues. I voted Remain I think due to 'better the devil you know' and 'lesser of two evils' type reasons. Also, most of my friends were remainers. But, I know people who voted Leave. Generally perfectly nice people, not a separate species. I wouldn't define someone by the way they voted in a referendum five years ago. We're much more than our voting choices, and people are complex.
Though, to be fair to the OP, she made clear it's when in shops, confronted by shortages that she feels this way. Maybe not always?
As stated up thread, shortages are due to a number of factors.
We can't go back in time to 2016. Climate change will bring very real food shortages globally, if we don't act now. So, I think expending emotional energy despising and othering people for the way they voted in a cloud of misinformation (not their fault) several years ago, is misplaced. We need to work together now, too much going on for anything else, in my humble opinion...