Person 1: the rules don't make sense
Person 2: there are too many rules, I don't understand them
At the moment you are person 1 but you are still more likely to follow the rules (or break the rules in a safe way) than person 2 who is interviewed on the TV frequently but needs the rules to be as simple as possible.
Ideally, the rules would be that you can meet in a garden but only doing so in a safe way. Here is part a, b, c and d on how you can make this safer. However, that stops us being "in it together" which, so the theory goes, is a way that ensures compliance is higher and a person who feels there are already too many rules will stop listening after "you can meet in a garden".Gardens have been included in these restrictions because in winter it is much more likely that people meeting in a garden will need or want to go indoors into the home, and as already explained a lot of the transmission of coronavirus is happening in people’s homes: https://gov.wales/coronavirus-regula...#section-39235
We know that the longer you spend with someone, the closer you get to them and the less ventilation there is the more likely the virus will spread between you. I am sure you are far more likely to want to get close and spend longer with a person you care about than a stranger at a football match so it is a riskier situation and while you can do it safely a Person 2 cannot.