Preppers hoard insane amounts of cans, frozen food and toilet roll.
A month or two is typical British stockpiling and is not "insane". The Govt is talking about telling the over 70s/75s to self-isolate for four months. If you are over 75 and all your kids have moved away or you didn't have kids, who will do your shopping for you? Suddenly those rare people who stockpiled six months stuff don't seem so stupid.
To constantly be worried about
I'm not worried. The point of prepping is to recognise potential disruptions to your daily life, realise that the Govt and the retail industry cannot or will not provide what you need during those disruptions, prepare to meet your needs during those disruptions yourself (hence the word "prep"), and be confident that you can handle whatever life throws at you because of your preparations.
getting a flu,
When you live on your own and work full-time, illness that prevents a shopping trip can have knock-on effects for the whole week. It doesn't have to be a long illness: a weekend migraine means I'm living off my stockpile for the next week because I wasn't able to go shopping.
being snowed in,
My mum lives somewhere where flooding and heavy snow are routine winter events, and yes they do stop her from going shopping. She gets regular power cuts and her preparedness includes fallback lighting, heating, and cooking arrangements. This isn't "insane" or "anxiety", this is anticipating disruptions to her travel abilities and electrical supply.
or any natural disaster is anxiety.
And yet here we are facing a natural disaster called "pandemic SARS-CoV-2 infection", aka "covid-19". It's not "anxiety" when the thing you are preparing for can actually happen.
The prepping for brexit was ridiculous
And yet the Brexit preppers are not the ones emptying the shelves right now...