The ins and outs of the law are all very well but do you really want to have an argument with an angry farmer/landowner when you’re trying to enjoy a quiet night out? A law allowing responsible wild camping would take away that risk.
This is a question of governance. In the current model in England and Wales, governing what is/isn’t your definition of “a quiet night out” is down tot he person doing it because they know what they’re doing carries a penalty of being booted out.
If you change the principle to permit responsible wild camping, you’ve put the onus on the landowner to prove what you’re doing isn’t responsible if they object to your being there.
And this is where the “ins and outs of the law” comes in because you’re effectively trying to turn a fundamental legal principle developed over the last 1000 years or so on its head in the pursuit of your definition of “a quiet night out”.
In effect, what this petition is asking for is not less law, but much more. Now, if you want to limit it to specified wilderness areas where you target the landowners to persuade them this is possible, maybe you have more chance. But England and Wales don’t have Scotland’s geography (or simplified land ownership – c400 people own half of Scotland!), so what you’re asking for is rather more nuanced than self defining “responsible” wild camping and thinking that’s sufficient to justify wholesale access to other people’s land.