I think this is the latest strategy, to try and get people terrified again.
Young people particularly targeted because they're deemed, rightly or wrongly, to be self-centred hedonistic ravers who don't give a shit about catching Covid. The government have recognised that the cases are going up among younger people who aren't fearful enough of the virus, so the new slogan is "Don't kill granny", because 'they must care about their Nan and Grandad even if they don't give a shit about anything or anyone else'.
I do think it's important that people aren't too complacent, but the other extreme is putting the fear of God back in people which isn't always healthy either. For the first time since March I was just starting to feel confident going out and about it a bit more and been to the pub/restaurant (following the guidelines and basic hygiene etc). Today, I did my weekly shop and felt that fear again inside, my confidence has gone again. And it's all from the hysteria that's back again this week.
The problem with the strategy is the simultaneous lobbying of "get back to the office" and "eat out to help out". The juxtaposition of government messaging will send people crazy with confusion, so it's no wonder people switch off.