Its either safe to meet people, or it isn't.
Nope. No, no, no. That's the WHOLE point.
This isn't and has never been about individual safety, other than for those who are shielding. It's about minimising human interaction to make things safer for ALL of us. And now, as restrictions are being eased, doing that in a measure, phased way, again, not because all interactions are suddenly safe or not safe, but because AS A WHOLE we can safely increase the number of interactions a bit.
So they are starting to phase that in and, imo, they have rightly started with the group of people who have had fewest interactions over the past three months: single-person households. These new rules aren't about reuniting families, or letting teenagers see their boyfriends or grandma getting to hug all her grandchildren. They're about people who have had ZERO physical human contact being allowed to start having some.
This really isn't complicated. If you live on your own, or only with children, you can now be counted as part of another household. That's it. Households can grow a bit. Everything else stays the same: no physical contact with people from other households. Shielding people still need to be shielded. If someone in the extended household gets symptoms, the whole household should self-isolate. And so on.